Looking for CNC Mill Part I

[balsaman]

Drill, tap, CA, let dry, retap, screw.

That's the correct order.

Actually you can just drill, tap screw, but the CA method will be stronger.

E

[balsaman]

Tir,

Nice machine. You got farther than most....Adda boy!

E

[gjahnke]

I am getting ready to assemble the new machine I have been working on, having finally gotten the whole spindle issue worked out.

My original plan was to use some 3/4" CRS for the rails and a bearing setup like the guys at www.buildyouridea.com has set up. I was at the local welding supply place today and they had 26' of 1 1/4 chrome plated that the guy sold me for $1 a foot (they use the chrome plated stuff mostly for hydraulic shafts around here).

It got em thinking that maybe I could get away with using delrin bearings or bronze bearings for my X axis. Does anybody know how well the delrin bearings hold up? What about using bronze bearings?

Any input woudl be appreciated.

Thanks

Greg Jahnke

[jcyr1]

John,
I've trying to log on to the forum to get some FAQ's, but it will not let me in. I did register with the group, I think? What goes. And how can I get to your support?
Jcyr1

[crankorgan]

Did you Email me? I can't see who you are. Did you buy something?

[jcyr1]

John,
I thought I e-mailed you when I signed up for the group, but evidently that's not the case. Yes I purchased a set of plans for the "Morph". Can't remember the exact date, it was lately. My name is John Cyr and I live in Surprise, AZ E-mail addr: jcyr1@cox.net. Do need to do anyting else? If so, what is it? Looked at your plans and I know the mechanical portion is do-able, my only concern is the software. I am definetly lacking in that department. The electronics should not be an obstical for me. Thanks for the help
John

[crankorgan]

John,
I will click you in if it comes back up EZBOARD is worthless. All the fields show private when people sign up. Lots of people from here try getting in so I have to screen everybody.

John

[jcyr1]

John,
Thanks I'll try again. I did get a message from someone that accsess was denied. Thanks
John

[Gary Blaylock]

gjahnke,

Sorry for the late reply. Yes the motors and controller seem to work fine. I ran a small retangle from Kcam and watched them work. I should be able to get most of my router built this coming weekend.

I know it has been said that you run the motors before installing them on a completed router that the project would never be completed. I promise my will be completed and the questions will start!

I'll post some pics maybe this weekend. Thanks for the help.

Gary

[gjahnke]

Great! Let us know how it goes!

[crankorgan]

If you spin the motors before you start the machine the deck becomes stacked against you. Instant gratification will do you in! If you hold off on spinning the motors the anticipation builds and you will stay excited about the project. A few people have spun their motors first and still finished, very few!
One guy bet me! He spun his motor first. With my help he was able to finish after a year. The old saying is a cart before the horse. Thousands and thousands of controllers and motors are sold. Only a few hundred machine get finished. You can read the excuses on Ebay when they sell their parts.

John

[RJG]

A question about CNC capabilities: Does CNC work best for certain arcs , circles, lines, shapes, and not for others? In general, does it work best for lines that can be represented by a formula? Or, is it unlimited in that it can cut any line that you can draw. Are there limitations in G-code? Are there some shapes that come out jagged?:confused: :confused: :confused:

[crankorgan]

RJG,
How many steps per inch with your motors, controller and leadscrew. A fine thread leadscrew produces a smoother cut but the machine is slower. The better software has constant contour for smoother cutting. Software like TurboCNC stops for each segment of a circle causing a ragged edge.

John

[RJG]

John,

If I want to CNC-route a non-gemetric shape, can I expect a "what you see is what you get" going from picture transfered to G-code then to the CNC router?

[balsaman]

It's not quite that simple, but even very wierd lines get converted to gcode just fine as very, very many little straight lines. They can be as small as a couple thousands of an inch long each. Turbocnc stops at each of these lines, but it all happens so fast that it's like one continuous motion, especially at the speed that most home made machines run at. Some of the faster machines benefit from constant velocity contouring (where the software "looks ahead" to see whats comming next, instead of stopping, looking, and then go again..which takes a few tenths of a millisecond or so). Arc and such that can be mathematicaly calculated are done as you say, as arcs. It depends on how it is done at the cad level.

Yes, what you see is what you get, as long as the machine is built straight enough.

E

[balsaman]

Here is a video of my machine cutting speed 400 motor mounts from 1/16 ply

www.e-zflight.com/files/cnc.mpg (8 megs not for the bandwidth challenged!)

right click and save target as...

E

[crankorgan]

RJG,
There are a few programs that take BMP files and turn them into GCode. The best results comes from a vector type drawing program that produces STL files. The best results requires drawing skills or lots of money.
What are you looking to do?

John

[balsaman]

John is correct. The thing that holds me back is my lack of 3D Cad skills. That said, if you can do 2D CAD, you can cut virtually anything "out" of a sheet. Going from bmp to gcode is for the most part not worth it. The gcode is sloppy and slow and cumbersome. The best way is to go from bmp to cad somehow (usually manually) and then to gcode once you have the cad file cleaned up.

Eric

[crankorgan]

Some versions of TurboCAD come with a small version of Corel Draw. It will take a BMP and turn it into a DXF. So simple line drawings can be scanned into you computer and turned into a DXF.

This is part is very important! The DXF created with Corel will be very random. When you convert it to a GCode it will have more traveling code than cutting. Run the DXF through the ACE converter to tighten the code.

Or you can put the DXF into TurboCAD and do a TRACE in a new layer and color. Trace the drawing the same way you want it to cut. Try to trace the drawing in a clockwise or counter-clockwise direction. When it gets converted to GCode it will be tight. A tight GCode spends more time cutting than traveling.

Having a fast machine with a bad GCode is the same as a slow machine with a tight Gcode.

[uscra112]

Mmmm, kinda like one of the many criticisms of Microsoft, methinks.

Not that I'm about to run out and buy Corel, but I have downloaded and/or bought several raster-to-vector converters, and none of 'em will work well on anything but the very simplest drawings. I have to trace everything anyway. I'm still working on a Fairchild FC-2W 3-view scanned in from the lovely George Clapp drawings. I must have 100 hours in on it by now . . .

[RJG]

Thanks for answering my questions everybody.

RE: What do I want to use CNC for.

I would like to do some antique style wood carving stuff (curly-ques, I'vy patterns, etc).

I have been taking an adult education wood shop class at night (at local High School) once a week. They have a large CNC machine (about 4X4 feet I beleive). No one is using it. Maybe I should learn to operate that machine before I make my own. Class begins again in about two weeks. Anyone here want to prep me on how to get started on the machine? Obviously I should follow the tips on this thread and prepare a G-code file. However, I'm not sure how to get it into the computer and operate the machine ( I don't think that the teacher knows either).

The machine has an interesting rolling gantry design. I will take pictures of the various parts and post them for you to see when class starts again.

[Tiramisu]

Hello,

I got a few questions regarding parts hold down for balsa. Without using a vac table I guess I need to put small bridges to keep the parts together correct? Putting in these bridges makes the machine travel all over the place taking forever to cut anything out. It does not seem to just jog up, move over a smidge and continue on its merry way. I am using TurboCad and KCam for now. I remember somebody mentioning the drawing order is important or perhaps running the dxf file thru some sort of "optimizer". Any help would be appreciated. Thanks.

[crankorgan]

Three messages or so back!

[Tiramisu]

good grief..if it was a snake it would have bit me! I tried using Ace but it really messes up the DXF file..it adds all kinds of new lines..the KCAM import always works correctly it seems.

I cannot find a Trace command in TurboCAD 7.1..am I going to have to just redraw the whole file if I add the bridges?

[crankorgan]

There is no Trace command. You trace the drawing in a new layer and color. You trace the drawing the way you want it cut. Then delete the under layers keeping the trace. This is more efficient than some other methods.
When the DXF gets converted to GCode it will cut just like you traced it. I do PCBoards this way. I can overlap the start and finish cuts. ACE sees overlaps as unecessary and takes them out.

[Tiramisu]

Cranky,

Ok thanks..I did what you said and I got rid of all the travelling. Thanks!

[RJG]

Can anyone here give me a tip on how to convert a JPG into something that can be imported to Turbocad?

Much appreciated.
Thanks
RJG

[techno_guy]

This is a great forum!!! I am new here and really stumbled across it by accident. I have built a CNC machine and use it for everything from routing circuit boards to cutting out parts for my model planes! I hope that I can contribut to this forum in a positve and effective manner.

[DICKEYBIRD]

RJG, were you wanting to convert .jpg to .bmp so you can insert it into a free downloaded T/CAD plan for tracing purposes? If so, just about any paint program (Paintshop Pro, Adobe PhotoShop, etc, etc will do that.

If you're talking about taking a raster file (.bmp, .jpg, .wmf, etc.) and converting directly into a vector format for editing in the CAD program, do a search here on raster to vector converters and you'll find all kinds of info. Trust me, you'll end up just tracing over your plan manually before you're done!

[crankorgan]

RJG,
I got a version of Corel Trace with the version of TurboCAD I bought at Staples. It will trace BMP files a couple different ways. You then save in DXF and touch it up in TurboCAD. Run it through ACE or trace it in TurboCAD to make it tighter. Converting from a BMP to DXF is easy if you just want to view the picture. Turning the DXF into a GCode can cause more moving than cutting. (Traveling Salesman Syndrome)

John

[RJG]

Thanks for the advice, all.

All I want to do is trace a *.bmp file in Turbocad. The trial version of Turbocad that I downloaded will not open *.bmp files. Frustrating!

I downloaded a copy of the freeware progam "Autotrace". I can't get tht working either.

[DICKEYBIRD]

CAD programs won't "open" .bmp files, you "insert" insert them into a drawing for tracing. If you're using T/CAD Learning Edition, just start a "New From Scratch" blank drawing, pull down the "Insert" menu, click "Picture" and browse your hard-drive to locate the desired .bmp. It will load on the screen and you then trace over it in a contrasting color with lines, arcs and curves.

Or, as Cranky says, store-bought T/CAD comes with a simple raster/vector "Trace" program.

Good luck and keep trying, you'll get it! :)

[RJG]

Thanks,

I got the *.bmp inserted.

[Tiramisu]

Hello,

My router only has 18" of Y travel so I need to join two balsa pieces to make a sailplane fuse. I tried using a dovetail type joint but it just not seem to work very well. Should I just cut a 45 degree angle or ?

So far I am not too happy with my results..I think I have a small alignment problem as I am not getting a square cut on one side of the table for some reason. What is a good way to align these contraptions?

This CNC stuff is not easy...

[techno_guy]

I have a question...how did you paste an image into your message?
Originally posted by Tiramisu
Hello,

I just completed my router and have a question on KCam. I am having a problem cutting thru the material. I have the Z axis table setup as follows:

Travel: 0
Normal Cut: .50
Deep Cut .50

The Z axis home is .50 above the table but for some reason the Z always stops at .125 above the table no matter what I do. Since this is my first experience at CNC (besides my foam cutter) I am sure its just a simple thing as I do not know what I am doing yet.

Attached is a picture of my machine that I just got running today. Its not quite finished as I need to finish painting and attach the vac table. I looked at Balsamans pictures and followed his ideas (thanks dude!). The tracks are rather cheap Igus Drylin N27 rails. Leadscrews, leadnuts, and controller are from cnclinx.com. So far I am happy with it as it cut a near perfect circle which I guess is a good test.

Anway..any help with setting up the Z on KCam would be greatly appreciated.

Thanks,

MM

[Tiramisu]

Hello..there is an option when you post a reply to browse for an attachment or picture file. Use the post reply button and not the quick reply to find it

[delphi7x10]

Thank You,

Well you have inspired me to try this, it is something I wanted to do for a couple of years, but finding this group gave me the push.

I have started to assemble the parts, have motors, a 4' X 8' sheet of MDF (can't buy any less here than full sheet), Just found bearing yesterday so have 24 of them now, and 3 K179 driver kits that someone else mentioned they used.

No doubt I will have many questions, but for now I will only ask a couple.

1 - in the steppercalc program, it gives a choice between 1 or 2 resistors, where do they go, on the line from the power supply, or do I need 1 or 2 per motor ? If per motor, then I take it 1 would go common line, or 2 would one on each coil. ( I am much more comfortable with the software than the hardware)

2- with regards to the rails for table, on all these projects I see black pipe, why not the galvanized or even the gas pipe with the 3M blue wrap on it? All home built projects mills, lathes, and cnc cutters always say black pipe.

3- why round pipe, why not square either steel or aluminium tubing? wouldn't it be easier to align square tubing, not to mention the bearing would have more to rest on?

Well thats all me questions for now, I am looking forward to cutting my first airplane out when this is done, I can't wait.

Rob:confused:

[crankorgan]

Rob,
I put Gas Pipe on the map! People laughed at the idea. Now they call it Black Pipe to hide the fact they laughed at Gas Pipe and then end up using it! Others say it's an old idea. Three years after the fact they find a similar design in an old magazine. Gas Pipe and bearings on a table saw. I re-discovered the idea and used it in the CNC hobby. Where were they for three years? Writing a book? Coming out with plans that they never get finished?

Many people have started a machine using Square Pipe after laughing at Gas Pipe. There are three things wrong with using Square Pipe. One is it won't sit right in the adjusting blocks that use the four bolts. You can mount it directly to the base and cause a forth problem.
It's not as well made as Gas Pipe(not that Gas Pipe is so well made.) You can rotate Gas Pipe to find two good edges. Square pipe has other problems that are waiting for you! Think dust! on a round surface verses a flat surface. Wait! I just thought of three more....


John

[Tree_Magnet]

Hey BD i just saw the video cutting out s400 mounts wow thats really great. i finally have mine up and running and have really no complaints. Gas pipe is working fine :D .
so far the hardest thing that i have found with cnc cutting isn't 2d or 3d drawing or g-codeing its TIME. The time to build. I can draw a plan out in a couple of days, gcode in a couple of hours and cut everything out, but find the time to put it all together blaaa there isn't any. thats the problem with this hobby is cnc makes making a kit to easy and building the hard part :rolleyes: oh well my 2 cents is used up

Tom

[gus_452000]

John,
Back to the square pipe thing. Have found a very good source (free) of square, thick walled, hard aluminium pipe. Idea No.1 set the pipe at 45degrees i.e diamond shape and also set the adjusters at 45degress and the have the roller blade bearings sitting 90degress tight on the inside of the new square (diamond) shape runners.
Yes/No ?
Gus

[crankorgan]

Gus,
You just raised complexity of the machine. I use 45 degree bearings on Routezilla. Gas Pipe also!



John

[gus_452000]

Very good John,
I will just follow the all ready very good path left by yourslef and balsa man.
KISS is as they say the best way.
Cheers
Gus

[Tiramisu]

Hello,

After working on my machine for days I am happy that the machine itself is accurate enough for what I am going to do with it. I cut squares and circles and tried to align the machine as good as I could and it seems to work just fine.

The problem for me exists in my CAD files I believe. One problem I am having are issues with cutting out sections within other sections..such as a lightening hole in a wing rib. Do I need to put these types of things on different layers or ?

I tried both AceConverter and the stock Kcam conversion..both have issues. Kcam seems to always do the better job but it has too much traveling..Ace seems to be superior in this regard but has real problems with just a stock circle..it blows a gasket everytime I try to import one. Kcam has no issues with circles.

Any help would be appreciated.

[crankorgan]

Tiramisu,
In ACE there are things you can select before you convert. This will fix most circle problems. Balsaman is the expert in this department.
I use eight sided pads for my PCBoard artwork instead of circles. I found this allowed my DXF files to work in KCAM-ACE or Flashcut.

John

[gus_452000]

Cranky,
the 'murphy's law' bit about these machines is when you have built one, that will work half as well as yours or balsaman's, then you can use them to build a better one!
I have decided that I am going to build a small one i.e. 6" x 12" or so and when thats finished and working I will then consider a slightly bigger 1 say 12" x 24".
The emergency stop button does that kill the router spinning as well i.e. breaks all the incoming voltage or just the X,Y,Z stepper drivers?
And 1 last thing the current limiting resistors are they in series or ae they parallel to the stepper coils.
Many thanks chaps

Gus
Best thread I have ever found!

[crankorgan]

Gus,
Emergency stop depends on software and the controller board having a relay driver output. You can wire a Dremel so the relay shorts the motor when the power is removed. You would need a DPDT relay. Resistors go in series with the windings.

John

[gus_452000]

Many thanks fot that John

Gus

[crankorgan]

I just wanted to explain that the parts I use in my machines are not availible in countries other than the US ans Canada. Providing support for the plans I have already sold is taking most of my time. Selling plans is different then selling a novel. The more plans I sell the more work I create for myself.
I used to sell plans to other countries. Trying to help someone build one of my designs with parts found somewhere else is very time consuming. I had several people beg me for the plans. They claimed they would use them as a reference. After they got the plans they wanted me to convert inches to metric for them. One guy got nasty and he demanded I sell him the parts. This along with bouncing checks caused me to go the US and Canada only route. Please do not post solutions to this problem. All the solutions require more work from me. Just trying to ship to different countries is a pain in the butt by itself.

John

[Jojje]

So, if someone convert and sell it in europe, in own name, and only sending you money, you don't mind ?

(I'm only asking ;-)

[gus_452000]

John,
understand fully, I doubt if we in Blighty could have our own cranky but you never know. The daft thing is we proberbly have 'stuff' here that we can use but don't have an English virsion of you, looking at things the way you can. We will crack it and hope that you will let us bounce our ideas off you. We are all new to this CNC game and know 'nowt' as we say around here, whereas you have had years of experience in the game. So we will keep finding bits and bots and if we can ask you then thats fine by us.

Many thanks

Gus

[DICKEYBIRD]

Originally posted by Tiramisu
Hello,

Kcam seems to always do the better job but it has too much traveling..Ace seems to be superior in this regard but has real problems with just a stock circle..it blows a gasket everytime I try to import one. Wierd :confused: I use ACE for all my stuff and have never had any trouble with any entities other than ellipses. Circles of any size on any layer have converted 1st time everytime. May be an issue with your CAD program. If you have a .dxf file setup option in your CAD, try saving in an old ACAD r12 filetype.

I have to snap a multiline around an ellipse and delete the original to get ellipses to work for bulkheads & stuff.

Good luck! :)

[crankorgan]

The reason for my post, is whenever I answer people's questions here I get hit with Emails about selling to countries other than the US and Canada. I also get suggestions on how I should do it.
Maybe the people with all the great ideas should try producing plans and then supporting them. Talk is cheap and very time consuming. So please, if you have a question ask it here! If you read back through this tread you will see I have been very open with my info.
I just need to let people know why I only sell to the US and Canada. Been there, done that and then found the correct path.


John

[Tiramisu]

Hello,

Thanks for everybodys input. Well maybe it is a problem with my Cad program. I am using TurboCad standard 7.1. What seems to be the best choice that everybody is using?

Hey..I tried exporting as Autocad R12 dxf format and that works much better in Ace. In order to get the circles to work in Ace I had to explode the circle twice...now it imports into KCam without issues. I have been joining all segments with the join polyline option..maybe I should avoid doing that and keep it in pieces?

[gus_452000]

John
Have been looking in RS supplies (I think that's Radio Shack in the states correct me if I'm wrong) they do big resistors with a gold 'coloured' cooling fins built on. Would these would still need to be attached to a decent heatsink and would they need ne kept electrically insulated from the other resistors.

Many thanks
Gus
P.S. have been given 4 100oz unipolar steppers for free, any good?
I know they work a chap tested them for me and had them wired so they spun.

[gjahnke]

Those 100 oz steppers are no good at all. Just box them up and send them to me, and I will take care of them for you ;)

THere is no such thing as too much heat sink

[crankorgan]

Gus,
The gold resistors with bolt mounts need a aluminum heatsink. I like sand or tube shaped resistors which don't need a heatsink.

John

[gus_452000]

Right I will keep the steppers for the moment (thanks for the offer anyway) they have little stubs on the back of them and 1 has a liitle box with more wires on it. Chap told me it was an encoder? is he right and do I need it?
I had the MDF delivered today WOW, how heavy these 2 chaps to carry one 8 x 4 board 1" thick, I'm thinking lazy whatists. Then I wished I had the store cut it to 4 x 4 anybody ordering MDF not needing a peice bigger than 4ft GET IT CUT BY THE STORE.
So I will take your advice John and get the standard resistors, and have decided to built a slightly bigger router board pointless using 100oz steppers on a 12" x 6" router board.
Does this MDF need a proper blade in the table or band saw? Can you work it like normal wood?

Thanks again to all for the help so far and will start posting pictures of my work (appologise already for the standard of the construction that will be my fault, not by design but well the best made plans of mice and men etc.)

Gus

[colinc]

Gus,

MDF is pretty hard on tools - use a TCT blade in your table saw, most bandsaw blades will blunt pretty quickly on MDF so don't use your best one.

Colin

[xairflyer]

Circular saw is the job for cutting the 1" mdf. Clamp a streight edge to the sheet and run the saw along it.
You will end up with nice square edges.

Cranky will be shocked !! You seen your motors turn before you built your machine !!

[gus_452000]

xairflyer,
well the guy said I could have them and I have a house full of stuff that doesn't work, so when he asked me if I wanted to see them work I said 'yes'.
The rest of the stuff in the house that doesn't work is being kept for spares but alas my wife simply does not understand how important box's of unworking stuff is, she calls it 'c**p' and that it should be chucked out.
Will they never learn!
Gus

[NewCADOnBlock]

I found some material that looks like it would make good rails for a machine. Has anyone used closet hanger bar (http://www.closetmaid.com/Look/Product_Catalog/product.cfm?item=2058) ? It's about 3/4" od, with a durable, smooth, hard factory finsh. It looks like rollerblade wheels would run real smoothly on it. Does anyone have any experience with it?

Thanks

[gjahnke]

Gus, my wife also thinks all my treasures are junk! She just doesn't understand that I NEED all that stuff for my tinkering, and that NO, it cannot be stored in an old garden shed.

Gus, I have some of that stuff hanging in my closet. It tink that it would depend on what you want to do with your machine. The closet rod won't take much of a point load (which is basically what your bearings are) and it isn't made of very good steel. I thing that if you are planning on cutting more than just foam you will likely end up with "tracks" in the bar. AS weird as it sounds, Crankys gas pipe solution really does work well. Sand the pipe and spray a coay of krylon on it and it is really smoothe. Alternatively, you could get some CRS in the diameter you want and save th sanding. You could also find some heyed shaft at a salvage yard. Take one of your bearings and make sure that it will ride in the keyway, it makes for a pretty good setup. The shaft size is going to be at least 1"

[Gary Blaylock]

Here are a few pics of the router I'm building.

[Gary Blaylock]

pic

[gjahnke]

I finished my new spindle th other day and mounted a 1/2 hp motor on it. IT ended up being too heavy for a regular stepper to lift (even one of the big mothers you can get on e-bay). It would move the spindle, but not at any speed or you missed steps.

I found this page http://www.diywelder.com/alternatormotor/wireingphases.php

IT is about re-wiring an automotive alternator to be a variable reluctance stepper. I built one (I just happened to have an old alternator sitting around) and wied it up to my Z-axis. Worked GREAT after I built a heavier mount for it.

I couldn't find a controller for t that would take ste/direction pulses (it is a 3 phase motor), so I wired it direct to the parrallel port (make sure you protect you parallel port).

NOw, before everybody jumps up and yells "BUT IT ONLY HAS 42 STEPS PER REVOLUTION", Think this one through. I turned a 1/2"x20tpi leadscrew on my lathe. A 20 TPI leadscrew with a step motor that does 42 steps/rev gives you a resolution of .0011. That is fine for what I am working on, and the thing half-steps just fine, so you could get .0005 out of it if you really wanted to.

I have found that this thing can be turned at 3100 RPM (higher than that and it starts to heat up, though it does not loose steps. you run out of speed in your PP before you run out of motor capability). Which gives you a speed with the 20 tpi leadscrew of 155 IPM.


Anyhows, I just though I would pass on the info and verify that I have tried it, and it really does work.

[Gary Blaylock]

pic

[Gary Blaylock]

pic

[crankorgan]

Gary,
You need to clamp a board on your Z axis to simulate the router assembly at maximum extended length. Then flex it in and out with one finger. I bet you can get the Y rails to bend.

John

[Gary Blaylock]

pic

[Gary Blaylock]

Hi John,
I'll check, but I shouldn't get any. The rails are 3/4" drill rod bolted into aluminum plates on each end. The plates are then bolted to my uprights which are three layers of MDF glued together. The uprights will be bolted all the way through into the base with 3/8" all-thread. (I routed two grooves through each before glueing up)

[Gary Blaylock]

John,
I forgot to mention that the uprights will not be as tall as in the pics. I will have 4-1/2" of travel in the "Z" axes. As soon as I get my router mounted and set the depth I will trim the uprights.

[crankorgan]

Gary,
Still run a test. Going for 4" might also be a problem. You only need to bolt a board off the Z to act as a lever.

John

[Gary Blaylock]

Hi John,
I'll test for flex this Sunday and let you know. Going to the B'ham Heli fun fly and leaving at 5 am in the morning!
I have got to get off this computer and get some sleep.

[gus_452000]

Hi all,
yes have taken note on the rail situation but I'm going with 20mm (3/4" ish) ground stainless steel shafts all round, and using pillow blocks with linear bearings, however thanks anyway.
My design is a bit of balsaman's and xairflyer's mixed up with some very good advice from cranky mixed in for good measure.
I have just found out that the wife has sold the house so everything will have to go on back burner while we find another one to buy (with an even bigger workshop, she wants more bedrooms?). WILL THEY NEVER LEARN!

Will keep in touch as construction will have to wait till we move.


Gus

[amirgeva]

I'm joining this party a bit late, but better late than never.
I've just finished reading most of this (long) thread. Took me about a week, but taking care of my 6 week old baby takes precedence.

I think I have most of the issues figured out from all your great posts and have started looking around for the materials.
I have ordered the steppers and controller from Dave Rigotti. Hopefully they should arrive in the next few days.

The one thing I couldn't figure out from the posts is how to make the plastic slides for the Y and Z axis. I liked the idea of using different size L shape aluminum to create the rail, but the slide is still not clear.
Can bearings be used on these instead?

Regarding software I am much less concerned. Programming being my first hobby, I intend to merge it into this project. Perhaps I'm over ambitious, but I intend to write all the software from scratch. This includes the CAD, conversion to GCode and the Direction/Step interpreter/driver.
I also plan to share those pieces of software free once they're operational as a token of my gratitude to all the people here.

This certainly has the potential of becoming a third hobby after programming and RC, but who cares, as long as I'm having fun.

[DICKEYBIRD]

Originally posted by amirgeva
Perhaps I'm over ambitious, but I intend to write all the software from scratch. This includes the CAD, conversion to GCode and the Direction/Step interpreter/driver.Hey Amir, while you're at it, would you put a few minutes aside to get nuclear fusion working for the home hobbyist, and also take care of that pesky perpetual motion thing. Oh yeah, one more thing, can you help me with my taxes? ;) :D

ps: Welcome aboard friend! :)

[amirgeva]

Originally posted by DICKEYBIRD
Hey Amir, while you're at it, would you put a few minutes aside to get nuclear fusion working for the home hobbyist, and also take care of that pesky perpetual motion thing. Oh yeah, one more thing, can you help me with my taxes? ;) :D

ps: Welcome aboard friend! :)

DICKEYBIRD,

I'll stick to what I know how to do. :p

Here is an example output of one of my cad programs, given airfoil coordinates and some size/ratios, it generated the template for my latest wing rib. I would have loved to cut that with CNC.

[clipclop]

amirgeva,
Its good that you are able to do the programing and are willing to share it with us . As modelers its dificult to justify the cost of softwear esspesially as we dont make money from it .
Stewart

[kfong]

Nice to know that it works, but it sure seem like an awful heavy motor to use. What about a regular stepper and a 3 to 1 belt ratio? What kind of drivers are you using. Short of building a customized driver just for the big motor and having to worry about all that extra weight. The highest rated module we could find only does 3amps at 55 volts. We have the design online. Did you build a discrete driver board with fets?

Kin Fong

http://www.embeddedtronics.com/

Originally posted by gjahnke
I finished my new spindle th other day and mounted a 1/2 hp motor on it. IT ended up being too heavy for a regular stepper to lift (even one of the big mothers you can get on e-bay). It would move the spindle, but not at any speed or you missed steps.

I found this page http://www.diywelder.com/alternatormotor/wireingphases.php

IT is about re-wiring an automotive alternator to be a variable reluctance stepper. I built one (I just happened to have an old alternator sitting around) and wied it up to my Z-axis. Worked GREAT after I built a heavier mount for it.

I couldn't find a controller for t that would take ste/direction pulses (it is a 3 phase motor), so I wired it direct to the parrallel port (make sure you protect you parallel port).

NOw, before everybody jumps up and yells "BUT IT ONLY HAS 42 STEPS PER REVOLUTION", Think this one through. I turned a 1/2"x20tpi leadscrew on my lathe. A 20 TPI leadscrew with a step motor that does 42 steps/rev gives you a resolution of .0011. That is fine for what I am working on, and the thing half-steps just fine, so you could get .0005 out of it if you really wanted to.

I have found that this thing can be turned at 3100 RPM (higher than that and it starts to heat up, though it does not loose steps. you run out of speed in your PP before you run out of motor capability). Which gives you a speed with the 20 tpi leadscrew of 155 IPM.


Anyhows, I just though I would pass on the info and verify that I have tried it, and it really does work.

[gjahnke]

Yes, you have to build your own driver. I couldn't find one anywhere that would habndle the load.

I actually tried a gear reduction for the z axis before I went this route. It was intolerably slow. My next option was going to be a servo. The machine will most likely end up with a servo anyway, since we are buidlign it for my brother and he is not technically inclined (don;t want him to have to mess with a jury rigged motor).

I just thought it was an interesting experiment, and while it is most likely not REAL practical for a mill, I can think of a few places it could be used where it would work really well. Of course, if you just really couldn;t see your way clear to drop the $40 for a servo, I guess it is a good option.

[balsaman]

Perhaps I'm over ambitious, but I intend to write all the software from scratch. This includes the CAD, conversion to GCode and the Direction/Step interpreter/driver.

I hope you mean you will write the "cad converion to gcode" software and not the "cad", AND the "conversion to gcode software". If the latter, you ARE ambitious. Most people consider the folks who just accomplish the machine ambitious.

E

[amirgeva]

balsaman,

Indeed I meant the latter. I may eventually skip the GUI part, since there's probably no point in redoing EVERYTHING (except for fun) but I definitely intend to create CAD utilities, in order to allow RC Plane specific actions (e.g. generating ribs, calculating aerodynamic balances) and CNC specifics like taking a 3D model and rearranging the parts into a 2D layout for efficient cutting.

Regarding complexity of such an endeavor, it's a matter of perspective. Since my expertise is software (including my day job), I consider the building of the mechanical part of the machine a more challenging task than building the software.

Amir

[Tiramisu]

Hello,

I am already thinking about a design for my 2nd machine as I am going to need something with more X travel down the road. Here is a picture of a router design that I have never seen built and was wondering if anybody had worked on one at all:

http://www.rockisland.com/~tiramisu/images/mockup.gif

It has a unique X axis in that the table is not attached to a slide but some sort of roller. Using something like this could save some dough as those big slides are huge bux. Any ideas on this design would be helpful.

Thanks

[crankorgan]

Tiramisu,
I have seen that before. If you build that machine as is you can call it the "Flex-O-Matic". Thin rails and a long axis is a beginner's mistake. The better someone can draw the worse their designs. Two different sides of the brain. For scale and design look at commercial designs. Some of the homemade machines starting to show up have design flaws. One in particular has been copied by several people. Watch out!

John

[Tiramisu]

Hi John,

Ok I figured as much. I guess I will have to spend the bux and do it right.

Yeah I know about design flaws. I made one in mine but it was not a big deal to fix it. I had the Y axis carriage only being supported by two shuttles..it twisted that way so I had to add 2 more. Dumb mistake on my part. Its just cheap MDF anyway right?

Thanks

[balsaman]

Look closely and you will notice it has a fouth axis (fifth?). The rails look very whimpy, as do the uprights. It's never been built..I guarantee you that. John is correct, it seems the fancier the drawing, the less likely it can or will become a reality (as a rule of thumb)

Eric

[crankorgan]

Eric,
Then there is the "Class Picture" of the parts. A person gathers all the parts he thinks he needs, then he posts a "Class Picture" of the parts. The picture comes in handy later on for Ebay, if the hot water heater does not break and get them.

John

[balsaman]

It's easier to draw in 3D and buy stuff than to build anything John. When it comes to the building part, people bail, and start drawing and buying for the next project. The "class picture", and ebay come in handy to fund the new wave of buying.

E

[Gary Blaylock]

Hi John,

I clamped a plate to my "Z" axis and performed the test. The only movement was the plate which I attached would bend some. My router will be attached to the plate of the "Z" axis in the pic. I could not see any movement there or in the rails of the "Z" or "Y" axis.

The rails of the of the "X" axis do have some movement. They are 53 inches long. I have included a pic of the fix. I used a piece of key stock, welded a washer on each end, took a lenght of all thread and ran it through an all thread connector. I put a locking nut on each end of the all thread. By turning a nut on either end the connector will travel from one end to the other. I welded a bolt on top of the connector and ran a lock nut down on it. This will adjust the sag from the rails. To install I will rotate the rails until the sag is at its lowest point. Then I will drill a hole for the bolt to go through. By adjusting the nut up I will be able to eliminate the sag. The adjuster will be bolted to the table 90 degrees to the rails. This will allow me to adjust the rails parallel to each other.

Gary

[Gary Blaylock]

Another pic

[crankorgan]

Gary,
It is very hard to see them move by eye. You need a dial indicator sitting at the Y rails. If you just use the machine for light cutting you will be fine. The odds are you will want to cut harder materials before you will need such a large Z. Are the rails 1" ?

John

[balsaman]

John,

He will be cutting model airplanes. It will be fine.

Gary,

Keep going, nice job.

Eric

[Tiramisu]

Guys,

I need a good basic 3D program to learn on and was wondering what would be a good first choice. I want to get into using my router for engraving, milling etc. TurboCAD does not seem suitable for this but it was great for 2D and my first CNC experiences. Any recomendations on a 3D app would be helpful.

Thanks

[AirX]

SolidWorks is an easy to learn 3D program that will interface with most 3D CAM solutions.

Eric B.

[Gary Blaylock]

The "Y" and "Z" rails are 3/4" drill rod which is solid. The "X" rails are 3/4 " sch. 40 stainless steel pipe. I really believe I will break a bit before the drill rod flexes.

I will know for sure once I'm up and running. I will keep everyone posted. Hope to have it running in about a week or two.

Gary

[ger21]

Originally posted by Tiramisu
Guys,

I need a good basic 3D program to learn on and was wondering what would be a good first choice. I want to get into using my router for engraving, milling etc. TurboCAD does not seem suitable for this but it was great for 2D and my first CNC experiences. Any recomendations on a 3D app would be helpful.

Thanks

Right now you can get trueSpace 4 for $79 at http://www.caligari.com. It's not a CAD program, it's a 3D modeling and animation program. The current version is about $600, but V4 is an excellent deal. A very powerful program worth considering. Check out the website.

Gerry

[amirgeva]

I got the motors and the controller. Yay!

From what I've seen on this thread, I liked the phoenix design the best. Since I can't get the original parts used to create it (outside the US), I will try to create something similar.

The only major problem I'm dealing with is the Y axis. Would 3/4 inch think Delrin blocks sliding on 3/4 inch outer diameter aluminum pipes be good enough ?

[Tiramisu]

Solidworks and TrueSpace..they both have demos so I will give them a try. Thanks for the input

[Yukonho]

Aluminum pipes are a no-no. They will bend way too easily, use steel.
co

[amirgeva]

Ok, I'll get steel pipes.
The main question is: will delrin blocks sliding on pipes provide a smooth enough movement?