Looking for CNC Mill Part I

[HobbyCNC]

Actually, no I didn't know. Glad you like our products! Looking good!

Dave Rigotti
www.hobbycnc.com

[Gary Blaylock]

I'm having trouble with too much travel. I have a .dxf drawing which I did in Acad. The outside is cut but it goes back and plunges again on the outside cut outs. I have used Ace but still have the same trouble. In Ace, when converting, I select "Generate I and J Before Other Coordinates in Block". I have attached a file hoping someone can take a look.

Thanks,
Gary

[Gary Blaylock]

Here's a pic

[Jojje]

Hi Gary.

Explode every block, purge the drawing and try again, with only lines and arc's.

[gkamysz]

What kind of bits and feeds are you using to cut 1/4" Aircraft ply? One pass or multiple?

Greg

[ger21]

Gary, have you seen my g-code export AutoCAD VBA macro? You can download it here: http://home.comcast.net/~ger21/CNC/downloads/gcode2.zip

You'll have to use pedit to make everything polylines, but it will give you cleaner code than ACE.

Gerry

I'm having trouble with too much travel. I have a .dxf drawing which I did in Acad. The outside is cut but it goes back and plunges again on the outside cut outs. I have used Ace but still have the same trouble. In Ace, when converting, I select "Generate I and J Before Other Coordinates in Block". I have attached a file hoping someone can take a look.

Thanks,
Gary

[amirgeva]

Another motor has spun. I finished assembling the Y Axis. It moves nicely...
Now all thats left is to assemble the Z axis, and make the mount for the rotary tool.
Can't wait to see it working...

[furyflyer2]

Here is allot more pictures- http://cnczone.com/gallery/index.php?s=

[thrmaln]

Hey guys,

I browsed through the messages on this forum and was quit impressed with what is being done here. I work as a Linear motion and robotics designer and I design high precision linear motion stages every day and would like to put some to work in my hobby. My goal is to draw parts in Rhino 3d and or Solidworks then output it to Mastercam 8 to machine the parts. Most of the parts will be Lofted wings and the router will be cutting mostly pink and spyder foam. However , I have a few questions.

I plan to use some surplus linear motion equipment here at work, thomson pillow blocks, THK recirculating bearings and various BSA leadscrew materials. The machine itself will not be a problem but I have a few questions on how Mastercam interfaces with the machine.

If I buy a board kit (hobby CNC) that allows for home limits can mastercam be used to drive to the home limits of each axis then bump in and out to set the zero of the machine. I would like to be able to use jig fixtures to hold my parts and set some sort of an offset that the machine could repeatadly hit to avoid setup time.

Can I run Mastercam on stepper counts only or do I need encoders? For what we are doing, encoders is way overkill and with the low lead leadscrews coupled to a moter running on 400 steps per rev is just fine. If possible I dont want to add an Digital IO board to read encoders.

What router does everyone use? I could use a dremmil but the parts will most likely take about 2 hours to cut and that seems a bit long for a dremmil to run. I looked into an air router like dentists use which may work but I am not sure. I can modify a speed 400 brushless motor by adding a very rigid spindle extension to build something similar to a NSK drill Spindle.

Since I plan to use Vacuum to hold my parts and fixturing I need a vacuum that can pull some serious CFM as well as not burn out due to heat. Any sugestions on this as well? WIll a PIAB air powered Venturi work?

Any sugestions will be greatly appreciated,

Marc Webster

[furyflyer2]

Here is some very long reading but here you go- http://cnczone.com/forums/forumdisplay.php?s=&forumid=48

[ger21]

MasterCAM doesn't control your machine. You need something like Mach2, at http://www.artofcnc.ca , or TurboCNC, at http://www.dakeng.com . MasterCAM will produce G-code that either Mach2 or TurboCNC will then run. Both of them can be homed like you mention above.

Steppers don't need encoders, neither Mach2 or TurboCNC will read encoders anyway. A stepper system with encoders will cost a LOT more than what I've already mentioned.

Porter Cable Routers are pretty popular.

You might want to check out the CNC Zone, http://www.cnczone.com, for more information

[amirgeva]

X Y and Z are complete.
All I need now is to create the mount for the cutter.
Am I bugging people too much with these posts? :)

[HobbyCNC]

NO! Not at all! Keep 'em coming!

Dave Rigotti
www.hobbycnc.com

[bgriggs]

Can't wait for the next post.


Bill

[G1K@home]

I have a cad related question for the gruop. I am using AutoCad 2005, and have a drawing that is larger than on sheet of paper. How do I tell the program to print the entire drawing tiled so I can tape the pages together for a full sized pattern?


Ryan

[parrisw]

Well I am reading through this huge post, I am maybe half way done, I am going to be building a 7th Sojourn, I got plans and picked of some MDF today, going to start building this weekend. So hopefull we will have another Canadian with a CNC.

Thanks

Will
Victoria BC, Canada

[amirgeva]

Machine completed!
Here is a picture of the improvised cutter mount made from kitchen cutting board plastic.
Now all I need to do is write the software :)

[Jojje]

I have a cad related question for the gruop. I am using AutoCad 2005, and have a drawing that is larger than on sheet of paper. How do I tell the program to print the entire drawing tiled so I can tape the pages together for a full sized pattern?


Ryan


Plot area
What to plot:
Window

[ger21]

Plot area
What to plot:
Window

What I'd do is draw a grid over you're drawing on a layer that won't plot. Then I'd set the scale to what you want, 1:1? THEN use window and snap to the corners of each square in the grid. Now that I think about it, you may want the grid to plot so that you can use the lines to trim the paper.

A lot of cheap CAD programs let you print tiled drawings, but not AutoCAD

Gerry

[amirgeva]

First cut, a sample wing rib using my current half baked software.

[Joules]

Hi guys, I don't know if this counts, but I use a Roland MDX-20 for making my model airplane parts. I only have an 8"x6" bed, but it is fine for parkfly style models... OK the thing cost thousands of dollars, BUT... It came ready to use, I found the software, in combination with Rhino 3D excellent. For those looking at an out of the box solution, who maybe don't have the skill, time or equipment to construct a machine, I can really recommend the Roland machine. I am a happy customer, no retail interest. I have a vinyl cutter, also Roland I use for cutting solarfilm, and plotting out my plans... It has made a huge difference to the quality, and quantity of models I make. Yep it's quite an investment, but so is trying to build that cnc router, they always seem to cost more than you bargain for, plus you still need to sort out the software as well, which Roland bundle with the machine.

Joules


Joules

[Gary Blaylock]

Gary, have you seen my g-code export AutoCAD VBA macro? You can download it here: http://home.comcast.net/~ger21/CNC/downloads/gcode2.zip

You'll have to use pedit to make everything polylines, but it will give you cleaner code than ACE.

Gerry

Hi Gerry,

I downloaded your software but don't know how to run it. I have Autocad 14 and when I pull the "Tool Menu" down there is nothing there for Macros. I did edit my G-code and fixed the problem with my test part but it was a lot of work. Hope your program will help.

I have down loaded Mach2 and I am waiting for my fund transfer to Pay Pal to register it. Right now it is limited on the amount of G-code it will run and a few other features are disabled. Mach 2 has so many features that I will never be able to use them all!

I have a few questions about "Motor Turning" in Mach2. When I get my motors running good so they will stop quick, the graph is basically flat on the bottom. Is this normal? Should I set the motors where they will ramp up to speed and then coast down after jogging or have I got it right by making them stop quickly after releasing the jog button? I seem to have good cutting speed, which is about 10 ipm. Is there some way to guage this and determine my top speed cutting speed?

Thanks,
Gary

[G1K@home]

I fi have a 3-d part drawn in solidwork, what can I use to convert it to G-code? I have been using ace to go from autocad to g, but for wing ribs and thing of that nature, 2-d has been acceptable.

Any suggestions?

Ryan

[Jojje]

I fi have a 3-d part drawn in solidwork, what can I use to convert it to G-code? I have been using ace to go from autocad to g, but for wing ribs and thing of that nature, 2-d has been acceptable.

Any suggestions?

Ryan

I save as to ACIS (*.sat) and use insert ACIS file in AutoCAD. Explode it, and delete everything I not need, then u know the rest.

/// Jojje

[ger21]

I fi have a 3-d part drawn in solidwork, what can I use to convert it to G-code? I have been using ace to go from autocad to g, but for wing ribs and thing of that nature, 2-d has been acceptable.

Any suggestions?

Ryan

Do you want to mill it in full 3D? If so, try MeshCAM, http://www.grzsoftware.com

Gerry

[ger21]

I downloaded your software but don't know how to run it. I have Autocad 14 and when I pull the "Tool Menu" down there is nothing there for Macros. I did edit my G-code and fixed the problem with my test part but it was a lot of work. Hope your program will help.

Gary, I think you need to use at least AutoCAD 14.1. 14 doesn't have VBA support. I'm not sure if anyone's tried it in 14.1, but it should work. I know people have used it in 2000.

For your Mach2 questions, you should ask on the Mach2 Yahoo group.

Gerry

[gkamysz]

I have been using Meshcam. It's an easy program for 3D parts but you have to understand it's limitaions. First it does't cut true arcs. second it genereate G-code on a "grid". That means it rounds cutter position to a grid point. The density of the grid can be adjusted. If you set resolution high, processing can take some time. Depending on tool size and grid size actual part dimensions can be slightly different than what you designed. But if the accuracy it gives is enough for you, then it's waterline finish cutting makes fast work of 3D parts compared to many other softwares. The waterline cutting is still in development it seems as it won't work for everything, but it worked for my parts. One part I ran through the typical Gcode software would have run on the mill for 48 hours plus, Meshacam cut it in 3 hours.

Greg

[ger21]

I have been using Meshcam. It's an easy program for 3D parts but you have to understand it's limitaions. First it does't cut true arcs. second it genereate G-code on a "grid".

Greg

MeshCAM does exactly what it was designed to do. Cut 3D objects without spending a ton of money on software. I don't know of any software that does 3D arcs for under $5000.00. Those require the software to know where edges of parts and individual surfaces are. MeshCAM reads .stl and .dxf files, which by their nature don't contain that information. They are just composed of individual triangles that may or may not be an exact representation of the original model. This could be one reason for the accuracy issues you mentioned. Nothing else does what MeshCAM does for the price. You can't always have your cake and eat it too.

Gerry

[gkamysz]

Gerry you are right, that is exactly what I found. However, if someone thinks they will cut molds or a round circle with it............ If you aren't aware of how it works you'll have trouble. I tried DeskCNC and found it can't cut a vertical wall, it's built into the software by the designer. Other than possibly spending the cash for the hobbyist version of Dolphincam, the software will be the limitation of any reasonably accurate mill setup if you intend to cut metal.

All of these inexpensive softwares must operate on the same principle. For example I want to cut a 10mm square. Meshcam generates Gcode while set to .05mm grid, but the code describes a 10.05x10.05 square unless I set my grid to .005mm. Setting the grid that small is possible but it would take a very long time to process. The error is due to using a .25" cutting tool which has a radius of 3.175mm, which Meshcam rounds to 3.2mm. Obviously for cutting a square I'd write the code.

Greg

[ger21]

Gerry you are right, that is exactly what I found. However, if someone thinks they will cut molds or a round circle with it............ If you aren't aware of how it works you'll have trouble. I tried DeskCNC and found it can't cut a vertical wall, it's built into the software by the designer. Other than possibly spending the cash for the hobbyist version of Dolphincam, the software will be the limitation of any reasonably accurate mill setup if you intend to cut metal.

All of these inexpensive softwares must operate on the same principle. For example I want to cut a 10mm square. Meshcam generates Gcode while set to .05mm grid, but the code describes a 10.05x10.05 square unless I set my grid to .005mm. Setting the grid that small is possible but it would take a very long time to process. The error is due to using a .25" cutting tool which has a radius of 3.175mm, which Meshcam rounds to 3.2mm. Obviously for cutting a square I'd write the code.

Greg

MeshCAM does most things the last version of DeskProto did. DeskProto is $1500. STLWork is $400, but not nearly as user friendly as MeshCAM. Millwizard is $250. These all work basically the same as MeshCAM. DeskProto has more features. In my opinion, none of these are designed for precision metal milling. Although DeskProto shows some mold work on their website.

If you want to do precision 3D work, the next step up would be Visual Mill. But, the latest version of Visual Mill more than doubled in price. A good option from what I've heard is OneCNC, which starts at $1000 and goes up to $7000. Definately not for the hobbiest.

If your doing commercial work, you should be able to afford the high end stuff. For us home users, make do with what we have available. And be thankful MeshCAM came about, or you'd be using STLWork and be out $400.

Gerry

[gkamysz]

How exactly do you make do with these softwares? I haven't figured out a good way to design parts to work around the limitations of the inexpensive softwares. Have you tried running Meshcam at a very high resolution? I might let it run overnight tonight to see what happens.

Gerry, I'm not putting down Meshcam. It is by far the easiest to use and with the waterline finishing fastest out of all of them. It's also the least expensive.

Had I known this software accuracy issue to begin with I probably would not have built my mill. For the time and money I spent I could have purchased a lot of prototyping time.

I just looked at Deskproto's new V4. This may be what I'm looking for. Then again spending an amount equal to the machine on software doesn't sound all that unreasonable if it makes parts that are useful.

Greg

[ger21]

How fast is the computer you're using? I've only got a PIII 500 and even with low stepovers and high res models I've only had to wait 10 minutes at most. If you have anything less than a 1ghz machine, I'd recommend upgrading to something around 3ghz if speed is that much of an issue. What size are the models typically? I know very large models can take a lot more time.

What are you modeling your parts in? How detailed is the .stl? Can you increase the .stl resolution? I do woodworking, so the lack of real precision you're talking about doesn't bother me. I do some modeling in AutoCAD using Meshes, so that I can set the mesh density as high as I want to get more accurate. When you load your model into MeshCAM, does it appear to be faceted, or is it smooth. If it's faceted, you need a hiogher resolution .stl. That could be part of your accuracy issues.

Try the DeskProto demo. Although I have a feeling you'll get similar results, as it works very similarly to MeshCAM.

Gerry

[ger21]

Hey Greg, I just read you thread over on the CAD_CAM group. What kind of parts are you trying to make? Like Les said over there, I think you're using the wrong tool for the job. All the software mentioned above is not the right choice if you are making parts to assemble with tight tolerances. Depending on the parts, 2D (2.5D?) CAM would probably be the way to go. For flat bottom pockets and similar shapes, I'd try Les' SheetCAM. http://www.sheetcam.com It's pretty cool. I use AutoCAD and my own g-code exporter I posted a few messages back.

If you need to do complex 3D objects with high precision, It's going to cost you.

Gerry

[georgeg]

What I'd do is draw a grid over you're drawing on a layer that won't plot. Then I'd set the scale to what you want, 1:1? THEN use window and snap to the corners of each square in the grid. Now that I think about it, you may want the grid to plot so that you can use the lines to trim the paper.

A lot of cheap CAD programs let you print tiled drawings, but not AutoCAD

Gerry

As a refinement to this plotting method, you might want to create named views for each square in the grid. (Named A,B,C, etc) Then when you go to plot a full set, you select plot "View", work your way down the list of saved views and you know you haven't missed any when you get to the end. Plus, its faster than selecting the limits of each square each time you want to plot a square. If you're plotting on page sized paper, don't forget to allow for unprintable margins when setting up your grid.

[ger21]

Or set up paperspace layouts for each square. Then you can plot them all at once with one plot command.

Gerry

[gkamysz]

Well now I know what I was doing wrong with the softwares I was using. All of them will have the same accuracy. MeshCam is just as capable as the others. The others take just as much time as Meshcam. Now to cut some parts.

Greg

[RTaylor]

This is a fantastic thread, tons of info.
Randy

[foam_man]

http://www.cnclinx.com/ebay_xyz/dremil_cnc_no_e.htm

[ImWhoIm]

Hey guys!

FINALLY got through this entire thread and must say there is a BOATLOAD of information here! Excellent work and thanks for sharing all!

Myself - I ordered Crankies 7th Sojourn plans about 2 months ago, collected all the parts (spun the motors! :eek: ) Built the CNC Mill, and proceeded to connect the driver board(a Stepper3) to my computer supply - backwards! :eek: :eek: When the smoke cleared I discovered I had totally burned it out... :mad: I guess I let my arrogance get a hold of me (instructions? We don need no stinking instructions!) and well... been building different tool holders while I wait for my new driver board to be delivered.. Talk about frustrating! :( Better believe next time I WILL be double checking my connections!

The plans were exceptional BTW... I thought a few times I found errors but then discovered that I was reading or perceived them wrong and it all ended up going together without a hitch.

My machine has a 400W computer supply (40Amps at 5V and 14Amps on the 12V line), 3 - 6V 1.8 Deg/Step LM2 Steppers and a Generic Die Grinder with a flex cable for the "dremel". My ultimate goal is to use the machine to make parts for my robots with a good amount of precision. They will be cut in 1/8 and 1/4 plastic similar to the PVC I used in the CNC.

As far as software, I plan on using TruSpace 4 (I have the full package and am very adept at it) for the DXF creation (2.5D and minimal 3D) then run the DXF through ACE Converter or MeshCam to finally go through TurboCNC or Master5. I have 3 laptops here to choose from so one will end up in the garage to drive this thing. Having an interesting problem with Master5 though, When it runs on the laptop, it starts going through the setup and then hangs, beeping every second or so until I terminate the program.. Anyone have any ideas on this?

I would put some pics of my machine up but I can't seem to findout how to upload pics... somebody wanna help?

Have a great day!
Don

[Tim H.]

Hey guys, I'm a complete newbie when it come to this CNC stuff and I've read through about 1/4 of the 1900+ posts in the thread. I'm hoping you guys could steer me in the right direction and save me some fumbling around.

Here is what I want, and what I want to do with it.

CNC router to cut balsa, lite ply, and sheet foam.
I'd like a 40-44" cutting length, but I could go less if I had to.
precision - 1/64th or better
Easy to build and set up.

Could you guys suggest some setups for me. I've been trying to figure it out on my own and I'm going cross eyed from reading all the posts.

Thanks a ton!

Tim H.

[ImWhoIm]

Hi Tim!

I just got done building a CNC machine that can do most of what you seek. I got the plans from Crankies site http://www.crankorgan.com.

He has a couple plan sets there that are all based on materials available in your local hardware store and some other sources that are easy to find. I would suggest you go there and check it out!

Good luck!
Don

sorry, just corrected that address :o

[ger21]

Hey guys, I'm a complete newbie when it come to this CNC stuff and I've read through about 1/4 of the 1900+ posts in the thread. I'm hoping you guys could steer me in the right direction and save me some fumbling around.

Here is what I want, and what I want to do with it.

CNC router to cut balsa, lite ply, and sheet foam.
I'd like a 40-44" cutting length, but I could go less if I had to.
precision - 1/64th or better
Easy to build and set up.

Could you guys suggest some setups for me. I've been trying to figure it out on my own and I'm going cross eyed from reading all the posts.

Thanks a ton!

Tim H.

Try http://www.hobbycnc.com

Gerry

[ImWhoIm]

I know not a lot of people have been adding to this thread lately but I just had to share this with someone!

Got my new controller board in - A Stepper3 - and connected it up. After a few mishaps (motors wired wrong... DUH! :( ) I finally got the first movement out of my 7th Sojourn!! IT WORKS!! :D :D

Have spent most of the afternoon tweaking it up and figuring out the Axis and so on. I thought I was pretty clever in the way I found the backlash of the floating nuts installed in my machine...

For those of you who don't have a 7th, there are 2 rails down each side of the table. Screws go through the table and attach to the rails. So... I put a bit into the dremel (flex shaft actually) and connected a multimeter - one lead to the rail and the other to the bit. I then positioned the bit over one of the screws and lowered the bit till it touched the screw. The meter read 0 ohms. Then using Turbocnc's jog on the smallest setting I jogged the Z axis up until there was no more connection. Bingo! .027 Backlash! I repeated this a few times to verify and it was right on the money!

I repeated this step for the X axis by positioning the bit off the table and touching the side of the rail... .03 backlash.. entered the values and it is ready to run! :D (Y has no backlash of course due to the nylon bearing I am using).

Haven't cut anything yet but will this evening is I can figure out how to use Ace.

Hope you all have a great weekend! Mine will be! :cool:

Don

[crankorgan]

You can replace the Floating Nut with a solid block of Delrin and have almost no backlash. The Floating Nut prevents binding not backlash. I put it in the design to make up for poorly made parts and bad alignments. It is there to help guarantee success.

[ImWhoIm]

And success is what it gave me! :) Thanks again for the great plans Cranky! I do plan on replacing the floating nuts eventually however I am unsatisfied with how some of my other parts turned out (sloppy... :( ) so I think the first job for the cnc will be to make some beter parts!

Thanks again!

[ImWhoIm]

Hey guys-

Welp, Played with my machine last night and got variable results from my tests. I have been using a 1/8" straight cutter bit for the dremel in my machine... basically, the cutter is 1/8" diameter and 1/4" tall with a 1.5" shaft.

Tried cutting 1/8" and 1/4" PVC that I use for my robots... quite fuzzy but it seems to be cutting it very well. ;) I think the fuzzy is from the type of plastic it is... it's almost like a foam core sandwiched between 2 thin sheets and it's the thin sheets that are fuzzing. Also cuts the 1/2 PVC VERY cleanly (in .0625 passes). Problem comes when cutting wood or MDF. I've tried cutting at high speed with a low feed rate and high speed with a high feed rate (max on my machine is about 7.5 IPS) and the mdf (or pine board) ends up burning shortly after any real cutting starts :eek: . Needless to say (but I'll say it anyway) this makes wood signs and plaques and experiment in wood burning. Depth of cut doesn't seem to matter here, it just varies how deeply the wood gets burned. What am I doing wrong here? :confused:

Also wanted to cut some replacement nylon pieces for my machine (using the machine!) and no matter what I tried to use for feed rate or bit speed, it simply melted the nylon. :(

One other question I have - I seem to remember that many of you guys run your steppers at twice the rated voltage without incident. I am using a chooper board on my unit and at first tried twice the voltage (12V on 6V motors). The thing zipped along at 10-11 IPS which was way cool :cool: but after only a short time of idling, the motors were not so cool... in fact they were almost to hot to touch :eek: so I backed off on the voltage to 5V. They run alot cooler :cool: now but as I said before, the current IPS is 7.5 :(

Is it wise to run these motors at twice the voltage on a chopper board and if so, how hot can they get before damage results?

Thanks!
Don

[crankorgan]

Don,
First I would suggest a carbide cutter. They stay super sharp. If you have a StepperWorld board it is not a chopper. When you increase the voltage to the motors you also have to change the resistors. If the wood burns increase your feed rate or decrease the speed of the Dremel. Steel bits dull quickly on MDF you have to use carbide. Plexi-Glass and Nylon are not the best materials. PVC is a great test material. Shoot for chips not dust.

John

[ImWhoIm]

Thanks for the reply John-

I will see what I can do about getting a carbide bit (or 5!). Do you recommend Ball or Straight cutting bits (or both?).

The Controller I have is a Stepper3 controller. It can handle up to 3A per phase so it should handle the motors well.

Thanks again!
Don

[ger21]

Do you have the ROC? It's not a chopper, so you need resistors like john said. You might want to try some of these bits. http://tinyurl.com/ddd5

Gerry

[crankorgan]

Don,
The carbide are $9 to $12 each. Buy 1/8" shank with a 1/8" cutter to practice with. Ball or regular two to four flute. You need something that won't dull after 5 inches. The Dremel bit are only ment for wood and they dull quickly there also. If you increase your voltage you will need to change your resistors
on the StepperWorld board.

John

[ImWhoIm]

Ah.. Well that's what I get for assuming... sigh

GER21-

Yep - I have to ROC so I guess I'd better start looking for resistors so I can speed this puppy up! I have ordered some bit from Precise Cut so I will hold off testing till they get in.

John -

These are the exact bits I purchased (just now) so i am hoping with those and some new resistors I will have better luck! Do you think doubling the voltage to 12 volts (easy with the computer power supply I am using) Is enough or should I go more?

Thanks for all the info guys! Here to one of the best threads around! :D

Don

[ger21]

Make sure you slow the rpm's down, or the carbide will burn too. And go as fast as you're machine will go, if it's around 7 ipm.

If you can, I'd try to use 24V, if you can find the right resistors. Somewhere in this thread is a link to Balsaman's Steppercalc program which will calculate the required resistors for your motors with different size power supplies.

Just a little note for anyone contemplating either this stepper3 or the stepperworld controller. For about the same price, you can get a Xylotex that will probably give you double the speed, although it doesn't have terminals to wire up relays or switches. If you don't mind soldering, you can get Dave's unipolar chopper at HobbyCNC for about $80, which will also give you much better performance. Another good option is the bare board from http://www.embeddedtronics.com

I read a lot of messages from people that buy these unipolar drives and then find they just can't get the performance they were expecting.


Gerry

[HobbyCNC]

Make sure you slow the rpm's down, or the carbide will burn too. And go as fast as you're machine will go, if it's around 7 ipm.

If you can, I'd try to use 24V, if you can find the right resistors. Somewhere in this thread is a link to Balsaman's Steppercalc program which will calculate the required resistors for your motors with different size power supplies.

Just a little note for anyone contemplating either this stepper3 or the stepperworld controller. For about the same price, you can get a Xylotex that will probably give you double the speed, although it doesn't have terminals to wire up relays or switches. If you don't mind soldering, you can get Dave's unipolar chopper at HobbyCNC for about $80, which will also give you much better performance. Another good option is the bare board from http://www.embeddedtronics.com

I read a lot of messages from people that buy these unipolar drives and then find they just can't get the performance they were expecting.


Gerry

Gerry,
That would be from the Stepperworld and Stepper3 driver boards you are referring to in your last sentence above I hope?

Dave Rigotti
www.hobbycnc.com

[ImWhoIm]

Thanks for the advice Gerry

Just ordered a new 4-axis chopper board (the Kit from hobby CNC) and can't wait to plug it n and give that 12V another try. i decided to go with the chopper board because I didn't want to hassle with some super-hot resisters and introducing yet another way to get something wrong in the setup.

In the mean time I have been learning a few of the programs for CNC and have a couple patterns I want to cut when the new bits get here!

Thanks agian for your help!
Don

[ger21]

I was talking about the Stepperworld and Stepper3. I haven't used these, and I'm not saying don't buy them. I just see a lot of people that are dissapointed with the performance they get with them. I haven't seen anyone complain that they can only get 7" a minute with a Xylotex. Most get at least 30ipm (depending on machine configuration). I've heard good things about your new chopper too, Dave.

Gerry

[crankorgan]

The plain facts are, The Piker, HobbyCNC and several others boards are all twice as fast as the StepperWorld's basic board using the same motors and supply. The StepperWorld FET board is a little better than his cheaper one. The Xylotex board needs to be mailed back for repair and that seems to happen alot more than I think it should.

Now that HobbyCNC has come out with a chopper we now have a reliable high performance hobby chopper. I have hundreds of hours in on chopper boards. The HobbyCNC is a home run. I used to recommend Xylotex to my plans customers. Now a better board has come along. This is only my opinion! But remember I get alot of feedback from customers.


John

[HobbyCNC]

The plain facts are, The Piker, HobbyCNC and several others boards are all twice as fast as the StepperWorld's basic board using the same motors and supply. The StepperWorld FET board is a little better than his cheaper one. The Xylotex board needs to be mailed back for repair and that seems to happen alot more than I think it should.

Now that HobbyCNC has come out with a chopper we now have a reliable high performance hobby chopper. I have hundreds of hours in on chopper boards. The HobbyCNC is a home run. I used to recommend Xylotex to my plans customers. Now a better board has come along. This is only my opinion! But remember I get alot of feedback from customers.


John
John,
Thanks for the kind words. Yes we think our new chopper driver board is very robust! During testing we stalled the steppers, turned on and off the power, and killed the computer all in the sake of trying to smoke the chip. Never happened! Not saying it couldn't...WE could not get it to fail within any reasonable acts of God! In fact, we like this chip MUCH better than the UCN5804B which will soon be obsolete and no longer manufactured.

Dave Rigotti
www.hobbycnc.com

[Gary Blaylock]

Hi Dave, John, and Gerry

Could you explain what a chopper board is and the advantages? I'm using one of Daves packages and I'm well pleased. If I could get more cutting speed by using a chopper, this would be great. My controller is on 24 volts and I'm using Mach2. I have a Dewalt router attached which uses both 1/2 inch and 1/4 inch collets. I also have a varible speed control attached to my router.

Thanks,
Gary

[HobbyCNC]

Hi Dave, John, and Gerry

Could you explain what a chopper board is and the advantages? I'm using one of Daves packages and I'm well pleased. If I could get more cutting speed by using a chopper, this would be great. My controller is on 24 volts and I'm using Mach2. I have a Dewalt router attached which uses both 1/2 inch and 1/4 inch collets. I also have a varible speed control attached to my router.

Thanks,
Gary

Gary,
Glad you like our 125oz-in 31V 3 axis system. The transformer you use is 24VAC. This produces @ 31VDC under load. A "Chopper" driver board does not use those big heat producing resistors to control the current to the steppers. It does it with a 20KhZ cycled frequency and current sensing electronics to turn off the current at the preset level. Our 4AUPC will control currents from 500ma to 3A (3000ma). Along with a more efficient design you get much more RPM from the stepper before the torque drops to zero. With the steppers you have (125oz-in 7.4V 1A) you can expect to see at least double, maybe triple the usable RPM. YUP! hard to believe. We developed this new driver board to be roubust and very easy to assemble. In fact it has fewer parts than our UCN5804B driver board. Hope this helps explain the BIG difference between our two styles of driver board kits.

Dave Rigotti
www.hobbycnc.com

[ger21]

The Xylotex board needs to be mailed back for repair and that seems to happen alot more than I think it should.

If you wire it correctly, and don't supply more than 30V, you shouldn't have any problems. It is quite intolerant to incorrect wiring, though. Probably not for the inexperienced, but, if you know what you're doing, you shouldn't have any problems.

Dave, I have a question for you. With you're unipolar chopper drive, and an 8 wire motor, all else being equal, will you're board provide the same or less torque than the Xylotex? My PacSci motors are rated at 252oz-in bipolar parallel or series, but only 178oz-in unipolar. Would this be what I can expect?


Gerry

[HobbyCNC]

Gerry,
If that is what the steppers are rated for unipolar, then yes. Most steppers are 6 wire type unipolar in the 1-3A range.

Dave Rigotti
www.hobbycnc.com

[ger21]

Thanks, Dave. I'm assuming at some point that your board at 40+Volts would perform better than my Xylotex at 24V. If I find I need more top speed, I may buy a board from you in the future. Just need to finish building my router.

Gerry

[HobbyCNC]

Gerry,
We tested the Xylotec board with a Vexta 125oz-in 2A 6 wire stepper for a comparison. BOTH boards performed the same at up to 30VDC which is the max for them. At 40VDC our driver board did do better as fars as top speed, as expected. Considering that our driver board costs $8.77 per amp/axis as compared to $16.66 per amp/axis we consider our driver board an outstanding value based on power alone.

Dave Rigotti
www.hobbycnc.com

[trippme]

Where would I look for a CNC hot wire cutter? I know I can build one with the Hobby CNC components but I don't really want to or have the time to build it from components.

Ideas?

[ger21]

Gerry,
We tested the Xylotec board with a Vexta 125oz-in 2A 6 wire stepper for a comparison. BOTH boards performed the same at up to 30VDC which is the max for them. At 40VDC our driver board did do better as fars as top speed, as expected. Considering that our driver board costs $8.77 per amp/axis as compared to $16.66 per amp/axis we consider our driver board an outstanding value based on power alone.

Dave Rigotti
www.hobbycnc.com

Thanks for the info, Dave.


Gerry

[ImWhoIm]

Hiya Guys-

I know in order to get the best speed possible, you have to have a supply that will supply the voltage/amps necessary to push it. Right now I am using an "old" computer power supply... it's a big one at 400W so it has plenty of current but only +12V max.

Where have you guys been getting the higher voltage (40V and more) supplies one needs to drive the steppers to their max speed? :confused: I know enough about electronics to build one but would much rather avoid the time and hassle if I can. Any Advice?

Dave-

Got the Controller yesterday and am going to build it over the weekend! :D Thanks for the speedy response! :cool:

Don W

[furyflyer2]

Here are some toridial transformers and caps for PS 60v plus
http://cnczone.com/forums/showthread.php?s=&threadid=4848

[HobbyCNC]

Hiya Guys-

I know in order to get the best speed possible, you have to have a supply that will supply the voltage/amps necessary to push it. Right now I am using an "old" computer power supply... it's a big one at 400W so it has plenty of current but only +12V max.

Where have you guys been getting the higher voltage (40V and more) supplies one needs to drive the steppers to their max speed? :confused: I know enough about electronics to build one but would much rather avoid the time and hassle if I can. Any Advice?

Dave-

Got the Controller yesterday and am going to build it over the weekend! :D Thanks for the speedy response! :cool:

Don W

We use a transformer rated at 24-30VAC at 10A, a bridge rectifier at 35A 600V, and a filter capacitor rated at 2,000uF per AMP at 50V or more. Its a basic linear power supply. Fuse protect it on the AC and DC side. Use bleed resistor across the terminals on the filter cap rated at 2K 1W.
60V PS will smoke the chips! Max DC voltage is 44VDC.

Regards,
Dave Rigotti
www.hobbycnc.com

[PanzyPoof]

:) MAn has the E zone Changed! New Look all around!

Just fired up my Machine today first time in almost a Year as I haven;t been Modeling!
Been bussy and Away from Models Attention elsewhere :rolleyes:
But getting back into the Swing now :)
Oh ya reason Just finished building anouther Toy see Pic...

[lsippell]

Has anyone mounted their controller on the backside of the y-axis on a moving granty machine, and if so, were there any problems with vibration ect.?

As soon as an order for 6-conductor wire comes in, I'll wire mine machine up and be ready to spin the motors (other than the Dremel).

Thinking of the Dremel, I mounted it yesterday, and had the lead screw to the y-axis out and decided to see how it cut. I put a 1/8" rotozip carbide bit designed for ceramics in it, and was able to feed it by hand across a pine 2x4, 3/8" deep at apx. .75 inch per second!

Louis

[Spit4Me]

Hi Everyone,
first things first ive read a lot of forum but few have come anywhere near the quality of this one.
CrankOrgan i Humbley bow before the master of Homemade CNC, i have a problem in the fact that i cant find any Spec's on my Steppers other than the fact that they are 3Amp 2.57Vdc and as such havent been able to find the torque of these as i have unlimited access to these units i was hoping someone could tell me whether theyve got enough guts for the job

[crankorgan]

Hi Everyone,
first things first ive read a lot of forum but few have come anywhere near the quality of this one.
CrankOrgan i Humbley bow before the master of Homemade CNC, i have a problem in the fact that i cant find any Spec's on my Steppers other than the fact that they are 3Amp 2.57Vdc and as such havent been able to find the torque of these as i have unlimited access to these units i was hoping someone could tell me whether theyve got enough guts for the job

How many wires? If only four sell them on Ebay. If 6 you can drive them with the HobbyCNC board.

[HobbyCNC]

How many wires? If only four sell them on Ebay. If 6 you can drive them with the HobbyCNC board.

5, 6, or 8 wires work with our 3 or 4 axis chopper driver boards.

Dave Rigotti
www.hobbycnc.com

[ger21]

If they are 4 wire check out the drivers at http://www.embeddedtronics.com

Gerry

[Spit4Me]

sorry guys
theyve got 6 wires
and i got about 100 of them (approx theres to many to count)

Dave your chopper board sounds great but do you have any idea how much it costs to get anything from the States to Australia makes your chopper board bloody expensive

Just a small side note when you guys say Ozzy its "Ozzy" not Ossi please get it right

[ger21]

The 6 wire motors will still work with the embeddedtronics board.

Gerry

[crankorgan]

Just a small side note when you guys say Ozzy its "Ozzy" not Ossi please get it right

We use the word Aussie here. It's in the dictonary. It is not an insult or your goverment would not be using it.

http://www.aussie.com.au/

[HobbyCNC]

sorry guys
theyve got 6 wires
and i got about 100 of them (approx theres to many to count)

Dave your chopper board sounds great but do you have any idea how much it costs to get anything from the States to Australia makes your chopper board bloody expensive

Just a small side note when you guys say Ozzy its "Ozzy" not Ossi please get it right

About $14USD to ship the driver board. Not "bloody" expensive! I've shipped over a dozen "down under" since May 1st.

Dave Rigotti
www.hobbycnc.com

[Spit4Me]

i stand corrected

im not complaining about its use just its pronounciation
im just avin a go a you poor colonialists grasp o' da queens language (Ha Ha Ha geez i can dribble)

[Spit4Me]

Dave
whats the delivery time and how would you prefer payment to be made

[heyarnold]

Spit4Me,
About your motors, you say "theyve got 6 wires and i got about 100 of them (approx theres to many to count)"

Would you be willing to part with some of them? I wonder what it would cost to ship 3 of them to Canada, eh?

[HobbyCNC]

Dave
whats the delivery time and how would you prefer payment to be made

In stock ready to ship via Airmail Parcel Post. Contact us offline at mail@hobbycnc.com. Our order/contact web page has details.

Regards,
Dave Rigotti
www.hobbycnc.com

[BennyLaird]

i stand corrected

im not complaining about its use just its pronounciation
im just avin a go a you poor colonialists grasp o' da queens language (Ha Ha Ha geez i can dribble)

Good to see someone else having a go at cnc.

I'm just starting to build mine. I have the electronics, motors, software etc and most of the mechanicals. I'm in Werribee so not far away. Have to compare ideas etc.

Benny

[ImWhoIm]

John -

You may remember a while back that I mentioned my machine had some backlash to it and you suggested replacing the floating nut with nylon or delron block. Well, I stored this in the back of my mind as a possible upgrade to the system after I used it to machine some replacement parts for the gibs and guides. To this end, I made my parts file, ran it through ACE a, machined the parts last weekend. Tell ya what, seeing the machine working on a useful project was a pleasure to see! :cool: This weekend I looked at the parts closer and low and behold, the parts are unusable! :eek: On each Opposite side of the piece, one side would be straight and the other would be a stairstep with the part being wider at the bottom kinda like this:

+-------+
|..........|
|...........\
|............|
|.............\
|..............|
+----------+

This is a little exaggerated but the bottom was an exact 3/4 inch as it should have been with the top being 1/32 smaller. :( The only thing I can think of was that I was cutting all of the 16 pieces all at once and the slant/flat sides were a result of accumilated error caused by the backlask in the unit. :confused:

I used the machine again this morning to cut 2 nylon blocks to replace the floating nuts. The sides are very, very close to being perfect. I can see what appears to be only 1 step in the 1/2 inch it traveled into the nylon but the difference in width between the bottom and the top is so small, it doesn't even show up on the caliper I am using.

Anyway, drilled and tapped the blocks and mounted them, and ran a test program. the blocks are alot stiffer but I am sure that will work out. There was also one spot about 3/4 of the way through the travel of the Z axi where the nylon hung on the screw. I was really hoping it wasn't binding as I am all but out of nylon now but once I got it past that point, it seemed to work fine from there on out.

I am going out of town tomorrow for a week so I won't be able to see it cut again till I get back. :(

[crankorgan]

Make sure you put some motor oil on the leadscrew and on any surface where the guides ride. Put a drop of oil on your finger and spread it. WD-40 also works. I use Delrin for my drive nuts-guides and gibs. Delrin is much better than Nylon in several ways.

[ImWhoIm]

FYI-

In my replacing the floating nuts with nylon I earned a lesson and a trick I thought I would share.

After cutting out the blocks, I drilled and tapped the first one and in the process of installing it on the machine, I found out the hole was not straight through the nut as I had intended it to be. Not wanting to throw out yet ANOTHER piece of nylon (I didn't have enough to make a new one anyway) I mounted it by removing the old floating nut, putting the new nut on the screw and reassembled the axis. Making sure the all-thread was straight between the motor and the bearing, I positioned the bed over the nut (by looking throught the mounting holes) and marked the spots on the nut where the mounting holes needed to be drilled. I them disassembled the whole thing, drilled the holes, mounted the nut to the bed and reassembled the entire axis. Bingo! :D Works like a champ! No binding and, even though the nut is mounted crooked (who sees that but me anyway?) it runs smooth!

That was the tip... lesson learned? Use Johns idea of mounting the nut in a vise, drilling the hole in a drill press. Then use the press to also start the hole as straight as possible. I did this with the second nut and the allignement was almost perfect as predicted!

Thanks again for the plans and help John!

Enough from me for this week! ;)

Don W

[ImWhoIm]

John-

As for the oil.. did exactly as you said. Rubbed oil on all the moving parts and a little extra on the screw. Also readjusted the gibs and guides to eliminate some of the play in the X and Y Axis. They were binding a bit when I fitst tightened them up but the oil really helped in that regard as well.

I would have used Delron too but I couldn't find any place that would give/sell me scraps and I didn't know about the cutting board tip until after I built the machine. But to buy the delron would have been about 3X as much as the Nylon.... Maybe some day!

Don

[Spit4Me]

Heyarnold
send me your details and i'll get back to you about a price

Dave
Thanks for the response as soon as the boss loosen the purse string i'll order one

Bennylaird
sounds like we've gone about it in the oposite fashion ive almost finished my table with the X,Y completed just getting into the Z axis and i am building a gantry style Router to accomodate my giantstyle planes

[BennyLaird]

I cannot find a source of delrin downunder, anyone know where I can get some?

[Spit4Me]

I cannot find a source of delrin downunder, anyone know where I can get some?
easiest supply are those white plastic chopping boards you get from spoils for about $2.00 i think you should be able to join it together to give a usable thickness

[crankorgan]

Delrin is the brand name of Dupont. Acetal is the type of plastic. I get my Delrin locally or Ebay.

[NewCADOnBlock]

easiest supply are those white plastic chopping boards you get from spoils for about $2.00 i think you should be able to join it together to give a usable thickness

The chopping boards are not usually made of Acetal/Delrin. They are made of HDPE, High Density Polethylene.

NewCADOnBlock

[uscra112]

Y'know, if you contact a mill-supply house, (specialty business selling machine shop and industrial machinery repair supplies), you can buy a substance widely used in machine tools called Turcite, or Moglice, (trade names). It's a metal-filled Teflon, specifically made for slideway bearings.

Moglice used to sell a special epoxy that you cast-in-place to make slideway bearings. We used it several times and it was very effective. I have a lathe that was made that way at the factory. And I once tried plain old Devcon 2-Ton epoxy, a type now universally known here under the name of JB Weld, to repair a badly scored lathe carriage. It worked fine. Now, in all those cases the slides were lubricated with oil, which our slides generally ain't.

Y'know what else was used a lot? The old brown resin phenolic material.

[satchid]

How would this works, is there somebody that tused it.

http://www.loctite.com/int_henkel/loctite_epoxy/index.cfm?pageid=151&layout=2

Click on the last one.

Could this be used for the nut as well. How would it be done?

[uscra112]

This one in particular looks like the right stuff. . .

http://www.loctite.com/int_henkel/loctite_epoxy/index.cfm?pageid=151&layout=2

We did repair a bronze leadscrew nut with the Moglice epoxy. It worked. That was a very heavily loaded screw, too - elevation screw on a large radial drill - it held the whole weight of the head up - probably 2500 lbs. You needed a very smooth surface on the screw thread, and you had to use the right mould release agent. You let the epoxy "tack" for a specified time, then broke it loose by turning the nut 1/2 turn. Too soon and it would tear, too late and you would probably have the nut glued on the screw forever. I dunno if would work with threaded rod - too rough a surface. But nothing ventured, nothing gained.

[crankorgan]

Tapping a block of Delrin gives you both a drive nut and a drive bar. You want the nut to be softer than the leadscrew. Any kind of a steel epoxy would be a mistake. Making a drive nut out of bronze would be a better move. Turcite or Moglice are expensive. The trick is to make the drive nut two to three times the thickness of the leadscrew. This allows more threads to hit the leadscrew and prevent backlash. When it comes to cutting balsa or plywood a plastic drive nut works very well. It also works great for milling circuit boards.

[satchid]

Hi all,
This is surely an exelent tread on DIYCNC. I read all the post.
I am from Gent Belgium and making a small CNC machine with an effective size 30 x 40 cm.

Here ( http://www.devcon.com/devconcatsolution.cfm?catid=34 ) are many epoxi's that could do the trick I think but I have no experiens on them at all. Therefore Your oppinion is verry welcome.
Witch one in the liquid is good?

Willy

[uscra112]

99% true, Cranky - but using the right KIND of epoxy will make a perfectly good nut. There are epoxies specifically made for the job, as I linked to. Is it any easier than just tapping a block of plastic? No. I just thought it was an interesting tidbit.

3474 A&B is the product number. For light loads, any BRONZE or ALUMINIUM filled epoxy might work. Steel filled would indeed be a non-no.

[Coligny]

Dear Mr Crankorgan

I read your comment some months ago that I should not turn the motors prematurely, or I will never finish the project.

I first laughed, but it made me think. At that stage my project was standing still for 6 or 8 months, and that after I got the motors going.

I got myself re-motivated, and now my machine is malling bar a few software probs.

Thanks for the inspiration "cranky" as some call you.

Do you maybe know NINOS?

Regards

C.Marloth

[crankorgan]

C.Marloth,
Did you ever notice they don't run the motor on American Chopper until the bike is done? Your brain will trick you. It craves gratification. If you spin the motors first you will lose what the brain craves. Spinning the motors first is like reading the last chapter of a book. Only the most motivated people can recover from a motor spin :)


John