Looking for CNC Mill Part I

[crankorgan]

xairflyer,
Go to a paint store and ask about latex. Don't go to a department store.

John

[Bez]

I think Emulsion is what they call latex paint in Ireland and the UK.

But it looks thicker than what we have.

I watch DIY shows on BBC America and they call indoor paint Emulsion.

See this link...

http://www.johnsofnottingham.co.uk/Term-EmulsionPaint.htm

Aaron

[titewad]

What type wire and connectors do yoe use to connect the stepper motors?

[Jim Frahm]

This thread has been a big help. I've read it from start to finish over the past few weeks, and now I have a question for you guys. I've been gathering parts, plans, etc, and now I'm looking for software. I came across a G code converter called Quickstep ($55.00). Any of you familuar with it? I know you've talked about software in this thread, but I can't find it. The search function for this thread has been turned off. Thanks in advance,
Jim

[uscra112]

Latex paint is technically an emulsion - particles of non-aqueous material suspended in a water carrier. When the water evaporates the particles bond together as a coating film. Same as the water-base polyurethane varnish a lot of us use for covering foam airframes.

[crankorgan]

Catch-Air,
Most people use TurboCnc ($20)(DOS) to convert the GCode to motor movement. You can convert a DXF to a Gcode using ACE (Found free in the CNCPro package) or use KCam(Win)($100). The Flashcut Demo (Win) will convert a DXF to GCode.

Quickstep is a clone of KCam that does not let you set the pin numbers to most of the controllers out there. Maybe he changed it by now. Try KCam first.



John Cranky Kleinbauer

[Jim Frahm]

Crankorgan,

As always, thanks for the info. I just downloaded ACE. I'm really looking forward to your plans.

One more question for you: The bar holders you made with the 4 adjusting screw, what material did you use? I think I read PVC, but it looks like aluminum.

[crankorgan]

Catch-Air,
1/2" Grey PVC. Plexi-Glass will also do. Some people use MDF (Bogus)

John

[MrChips]

John,
Where can this Gray PVC be found? Don't think I have seen it in the home stores.
Thanks
Hager

[crankorgan]

MrChips,
Local Plastic supplier, Ebay, On my Links page there is a guy at Norva plastic that will sell you a nice amount cheap. He is also on Ebay. You can drill-tap or sand it all with standard hand woodworking tools. Unlike plexi-Glass it does not crack. Grey PVC is neat stuff. I turned several robotic guy on to the stuff. They got tired of Plexi. I use 1/4" and 1/2"

John

[MrChips]

John,
I checked Nova Plastics and they list five types of PVC, which one do you suggest?
Thanks
Hager

[crankorgan]

MrChips,
Tell Howard you want some Grey PVC 1/4" thick and some 1/2". Are you build one of my machines?
He sells some precut pieces that help with building my machines. Not all the blanks are there.

John

[Jim Frahm]

John,

Thanks for all your help and information in this thread. I ordered two sets of plans from you. I don't have the plans with me, so I'm sorry if this is answered somewhere in the plans. Is it possible/advisable to mount the two rails on the 7th Sojourn just like the Routezilla II?
As you advised MrChips, I will contact Howard for the grey PVC.

Thanks again and Happy New Year.

Jim

[crankorgan]

Catch-Air,
The flanged mounted pipe holds its setting better than the other designs. The 7th can be moved and used without recalibration. The pipes strengthen the base. People have milled circuit boards with the 7th. The Phoenix is designed for cutting out larger balsa parts and cutting signs. This requires less accuracy. The 7th can be made very accurate. There is also a private support of my main page.

John

[Tree_Magnet]

Well my router is up and running it's all based on crankys 7th. It is a simple an accurate design. if any one was thinging on building a router for the first time use crankys 7th plans. i am using xylotex 3 axis chopper driver board and am cutting 18 inches/min which isn't bad. the chopper driver is the only way to go i built another controller using lm298 chips a (couple of years ago ) and current limit resistors. it was a little cheaper but the xylotex driver is only $125 usd (about $160 cdn + 25 shipping)

Tom

[balsaman]

Tom,

What are you using for a power supply?

Eric

Happy new year everyone.

[Doug Blackmon]

Originally posted by crankorgan
Machspeed,
Try you local copier repair. Ask for 6 wire 5 to 6 volt 1 to 1.5 amp steppers. These will work with all the controllers out there.


John

I must say after spending a few days reading all this information has inspired me to build a CNC unit as well.

Just a little back ground about myself.

I am a Canon Copier Systems Engineer, Thats fancy talk for I work on copiers for a living.

Thay are full of stuff that is usfull for building a CNC router, The problem is for what I have seen in the newer Digital machines it Canon is using 5 Phase Stepper motors.

I have access to 6 and 5 wire configs of the 5 Phase units. I have been cross referancing and looking through older models (Analog) units for 2 Phase or 4 Phase.


It seems Canon favors VEXTA Stepping motors Mfg by Oriental Motor
www.orientalmotor.com

Is it possible to use the 5 Phase setup with alot of the controler kits avail now.

Like the HobbyCNC for example.

Or it the 5 Phase overkill and or to difficult to control.


I would also like to thank the major posters for supplying such great information on this subject. I wanted to build a Tabletop CNC unit a few years back but I put the project on hold.

Doug

[crankorgan]

Doug,
5 phase is proprietary. Only Oriental/Vexta and maybe one other company use it. 5 phase runs faster and smoother than 2 phase Unipolar (6wire) or BiPolar (4wire). Do you work for Cannon in NJ. I worked with Rick Yasson at TRW. The last I heard he was still with Cannon.

John

[Doug Blackmon]

So I guess I should dump the 5 phase idea, and dig deeper into my service manuals for some 2 Phase motors then.

I have been reading correctly Unipolar is the way to go?

No I dont work for Canon in NJ, that is one of the Service support devisions and parts warehouses.

I work for a indepent dealer in Eufaula Alabama. We are the oldest indepent dealer to this date from my understanding (over 30 years now). Most of the Canon employees I know work in the Atlanta office. This is on of the training building I goto alot for classes on new equipment that is produced.

Let me run this by everyone about using a vacume in the desigen.

There is two befents of useing a shop vac for what I see.
1- Using it like a clamp to hold your stock to the bed
2- Dust removal

Here is the two ways I have seen this achived.
1- Drilling holes into you stock table (Using a Vacum form machine method)
2- Attaching a hose clise to the bit of your moto tool to remove dust.

This came to me this morning as I got out of bed.
This would really only work with a Gantry system, but Why not extend the lower part of the gantry under the stock table and attach your vacume hose directly under your moto tool.
Of couse for this to work you would have to have a void of space under your stock table and you would have to drive the vacume hose just as you move your Y axis.

If everyone is still with me, I belive you could still remove dust via the holes in your stock table and still provide enoughj downforce to hold your stock directly under the tool.

I guess this ide could be designed into the 7th made by John (aka Crank). you would have to attach some sort of C to the Z axis so that it would allow the vacume attachment to go under the Gas pipe.

To help the downforce you could use the brush attachment that comes with the vacume. Let the brush ride against the stock table.

If I have time I will try to sketch something out to show visualy what I mean.

On a side note it seems to me that 1/4 20 allthread is the way to go to provide a smooth scale for moving the table and tools around?

Doug
Yo your Y axis on a gantry

[crankorgan]

Doug,
UniPolar is the cheapest way to go not the best. Vacuum hold downs only work on some parts.

John

[xairflyer]

I been collecting steppers everywhere and have got enough matching to get me started (all 1 to 1.5A) for my first machine.

What I want to know is the Amperage of the motor directly related to the torque.
i.e. is a 2A motor more powerful than a 1A or is this a stupid question.

[crankorgan]

xairflyer,
All things being equal, more current means more torq. But in the real world there are older steppers that draw lots of current and spin slow with poor torq.

For balsa cutting using a 1/4-20 threaded rod any NEMA 23 6 wire 1 to 1.2 amp 5 to 6 volt motor will work with all the low cost controllers out there. You can use a PC supply and some cheap resistors and you are good to go! If the current of the motors or the voltage is higher things start to go wrong.

If the motors want higher current then you will need to use two PC supplies with more expensive resistors.

If the motor voltage is higher a PC supply will have to be repaced with an expensive one. Controllers that can handle higher voltages are also limited.

Stay away from 12 to 24 volt motors or motors that want 1.5 amps per phase.

John

[Tree_Magnet]

BD i am using a 24v 4.5 amp powersupply i got from work ans a 5 v 3 amp for the logic.

Tom

[crankorgan]

Tom,
With a Xylotex and 24 volts you should be seeing a jog of 24 " per minute or greater. What Jog speed are you getting?

John

[kfong]

Hi Doug,

5 phase is not proprietary, just a little more complex. We designed one for our own use. Could you tell me more about the 5 phase motors specs you have. Perhaps we can work out a trade if it's something that I could use. We have a 5 phase design finished.

Unipolar is probably the cheapest way to go.

Kin Fong

Embeddedtronics.com

Originally posted by Doug Blackmon
So I guess I should dump the 5 phase idea, and dig deeper into my service manuals for some 2 Phase motors then.

I have been reading correctly Unipolar is the way to go?

No I dont work for Canon in NJ, that is one of the Service support devisions and parts warehouses.

I work for a indepent dealer in Eufaula Alabama. We are the oldest indepent dealer to this date from my understanding (over 30 years now). Most of the Canon employees I know work in the Atlanta office. This is on of the training building I goto alot for classes on new equipment that is produced.

Let me run this by everyone about using a vacume in the desigen.

There is two befents of useing a shop vac for what I see.
1- Using it like a clamp to hold your stock to the bed
2- Dust removal

Here is the two ways I have seen this achived.
1- Drilling holes into you stock table (Using a Vacum form machine method)
2- Attaching a hose clise to the bit of your moto tool to remove dust.

This came to me this morning as I got out of bed.
This would really only work with a Gantry system, but Why not extend the lower part of the gantry under the stock table and attach your vacume hose directly under your moto tool.
Of couse for this to work you would have to have a void of space under your stock table and you would have to drive the vacume hose just as you move your Y axis.

If everyone is still with me, I belive you could still remove dust via the holes in your stock table and still provide enoughj downforce to hold your stock directly under the tool.

I guess this ide could be designed into the 7th made by John (aka Crank). you would have to attach some sort of C to the Z axis so that it would allow the vacume attachment to go under the Gas pipe.

To help the downforce you could use the brush attachment that comes with the vacume. Let the brush ride against the stock table.

If I have time I will try to sketch something out to show visualy what I mean.

On a side note it seems to me that 1/4 20 allthread is the way to go to provide a smooth scale for moving the table and tools around?

Doug
Yo your Y axis on a gantry

[crankorgan]

kfong,
It's not proprietary but only certain people use it so in my book that's proprietary. Show us the circuit and then it will be public.

John

[Doug Blackmon]

Originally posted by kfong
Hi Doug,

5 phase is not proprietary, just a little more complex. We designed one for our own use. Could you tell me more about the 5 phase motors specs you have. Perhaps we can work out a trade if it's something that I could use. We have a 5 phase design finished.

Unipolar is probably the cheapest way to go.

Kin Fong

Embeddedtronics.com

I would like to be able to tell you more about the motors, but the part numbers on the sticker do not match what is on Oriental Motors web site.

Here is a link to all the 5 Phase motors in the Vexta Series.
http://www.orientalmotor.co.jp/cgi-bin/WebObjects/UPOMStep.woa/wa/F2?frameSize=60&seriesId=5CSK&typeNameId=1

I do know for a fact there 24 volt .72 step single shaft.
with a 2.36 inch Frame

That leaves three to choose from on there site.

Considering this motor is a scanning motor from a Canon imageRunner 330 Digital copier. So if I had to put money on it I would say its 59 oz Holding torque.

Again I have alot of equipment to look through so there is no telling what I may run across.

So let me know what ya think. Also if you have a control design to share using a 5 Phase motor please share. Im sure this could be used.

Doug

[Doug Blackmon]

Originally posted by crankorgan
Doug,
UniPolar is the cheapest way to go not the best. Vacuum hold downs only work on some parts.

John

Ok note taken..

As far as the vacume goes I noticed a few posts regarding the matter.

A vacume attached to the unit will be a must for me. Nothing worse than a messy shop lol. I just figured I would run that idea to everyone to see what everyone thinks. I for one have not built or used a CNC machine yet. So I have no real idea how much force is needed to hold your stock down.

Doug

[crankorgan]

Doug,
Those 5 phase will give you 500 steps per revolution. This will be smoother than a half-step drive. You will need a circuit that supports STEP/DIRECTION in order to use the motors with the software out there.
I suspect you will also find 4 wire BiPolar motors. These can be run with an Xylotex controller. If you find 6 wire steppers you can use them on a Xylotex or any other cheap UniPolar controller. Even a simple homemade one.
Keep looking. The 5 phase might be nice, but they might cause you to go off on a tangent.

John

[xairflyer]

I am going to use the three 1.2 -1.5A motors I have plus 6mm Stainless threaded bar and the super cheap unipolar drivers kits i got from Quasar with computor psu for my first machine.

Should I try to run my motors at thier rating i.e selecting the right resistor value to give the full amperage or should I just use say three 8ohm 25w and forget about it.

[Doug Blackmon]

Originally posted by crankorgan
Doug,
Those 5 phase will give you 500 steps per revolution. This will be smoother than a half-step drive. You will need a circuit that supports STEP/DIRECTION in order to use the motors with the software out there.
I suspect you will also find 4 wire BiPolar motors. These can be run with an Xylotex controller. If you find 6 wire steppers you can use them on a Xylotex or any other cheap UniPolar controller. Even a simple homemade one.
Keep looking. The 5 phase might be nice, but they might cause you to go off on a tangent.

John

Yea thay really seem like top notch steppers, and to top it off I have great shock mounts for them. The take off speed on the copier scanners are quick so the mount is a must. I figured the mount would help on my project.

Also if any one is interested in bearings I have a boat load.

Doug

[balsaman]

Hmm. If the 5 phase motors are 24 volt they may not be your best bet.

Vacuum hold down is great but usually needs to be suplemented with a clamp at the edges somewhere. I am currently adding this to my machine to hold down 3 and 6 mm depron sheets. It does not replace a dust collector tho so if you don't like dust you need both.

Unipolar drivers are cheaper at <12 volts but if you go higher voltage for more speed they get more expensive than a bipolar drive because you need to buy expensive resistors. You also need a higher amp powersupply because of unipolar drives are less efficient at higher voltage. All things to consider.

E-man

[crankorgan]

xairflyer,
The cheap Unipolar boards will work quite well with a PC supply and (8 ohm 20 watt) resistors. Get everything working first. The boards you bought have the 5 volt reglator on them? If so you still have to put a load on the 5 volts of the PC supply. Did you get my Emails?

John

[crankorgan]

Doug,
24 volt steppers of any kind are bad news! Keep looking!


John

[Doug Blackmon]

Originally posted by crankorgan
Doug,
24 volt steppers of any kind are bad news! Keep looking!


John .

Dont make me have to spend money... lol Thats cool, ill just tear some more old copiers apart tommorow..

Doug

[xairflyer]

No John never recieved any. when did you send them.

[crankorgan]

xairflyer,
You have to sign up globally and locally. I don't think the Email on this place works all the time.

John

[titewad]

hello
I building my first router and need a little help.
my plan is to use deskcnc with camtronics 3a bi polar chopper
wired to vexta pk268 1.5a 1 to 2 belt drive hooked to a 5/8 ball screw .200 pitch
with that said
how fast can i expect it to run?cutting and rapids?
mark

[crankorgan]

titewad,
Did you buy all that stuff yet? Pretty expensive equipment for just cutting balsa.

John

[xairflyer]

That's unusal as I have recieved numerous messages from other members of this group.

You can use xairirl@esatclear.ie

[crankorgan]

xairflyer,
I used two different methods off the Email I got from this place. The address you put here ends .ie
the one I got ends .de. Maybe you need to update your profile? Also Email me direct with what you bought and how. I got a bunch of people claiming to be you and they are trying to get into the Inner Circle after reading these messages.

John

[MrChips]

John,
Sorry for the delay, the holiday got in the way.

Quote________________
MrChips,
Tell Howard you want some Grey PVC 1/4" thick and some 1/2". Are you build one of my machines?
He sells some precut pieces that help with building my machines. Not all the blanks are there.

John
-----------------------
Thanks for the information on the plastic sheeting.
No, I'm didn't purchase one of your plans but I am using several of your "keep it simple (KIS)" tested and proven design items.
I'm retired and have more time than money to play with the design, and I know I have made mistakes and I'm willing to live with them. I frequent the CNCZONE and have recommended your plans to new builders so they don't make design mistakes.

You have a very good cross section of machine designs that enable a person to select a design based on their needs, ability and access to machining equipment.

Thanks again John,
Hager Hay

[xairflyer]

John

I checked my profile and all is ok only the one email as I have listed above. (gave me an excuse to upload an avatar !)

I will contact you direct.

[crankorgan]

xairflyer,
I got people asking me customer support questions here and people lying to me who they are. I will see you guys in the Spring when things slow down again. Right now I am in over my head with real and fake Emails.


John

[titewad]

John

no all I have purchased so for is the step and directiion from camtronics.
I am building this to run production. 1/4" dia 1/4 deep cuts in mdf and partical board.
Mark

[titewad]

sound like john is gone
anyone else like to help?

Mark

[balsaman]

It's hard to say how fast it will run. It depends on may things. Build the machine. Worry about speed later.

Eric

[titewad]

Eric

only have enough money to do this once
If it dont work the kids starve
the plans are about done
I ready to start cutting

Mark

[Doug Blackmon]

Originally posted by titewad
Eric

only have enough money to do this once
If it dont work the kids starve
the plans are about done
I ready to start cutting

Mark


I agree speed should not be a concern at this time. You look like you are trying to buld this from scratch without proven plans, Just as I am.

I am going to use the 1/4 20 allthread from my project just like John and others have done.

Of course speed is not a issues for me, I am using this project to help me learn. I dont build model planes like most of you do, I like scratch building sci-fi models.

The main reason for this learning curve is I am currently building a Nascar Winston cup car out of cardboard. This in turn will be fiberglassed over and I will construct a light weight chassis out of conduit.

The reason for this is I am a serious online racer using Narscar Racing 2003 software.

I plan on taking this sim one step further by building a motion platform to move the car. This is the easiest way to play with idea on a smaller scale that I might be able to use in my project.

Not to mention I have allways wanted a CNC machine. There is something about cool tools that I love.

Listen to John and Balsaman invest in the 1/4 20 allthread and work your way up. If you desigen you CNC right it should not be a issues to modify or change over to 5/8 ball screw.

I have spent several days reading all the posts in this fourm and have watched project start from paper to production.

From what I can see there is no reason in the word to buy expensive stuff for hobby use. All the cuts I have seen posted look top notch and right on the money.

Balsaman where did you purchase you E Stop button at I would love to get one just like that for my project.

Also on the 24 Volt motors that you recomend not useing. Is it a issues that the controler only supports I think like up to 30 volts it cant run 3 motors at 24 volts Being its 24 volts x 3


Thanks for all the information that is posted here, Its like a bible online for CNC.

Doug

[balsaman]

No, that is not the issue. Stepper motors are run at a greater than rated voltage to get more speed, and then scheme of current limiting is used to control the current (and heat). If you use 5 volt motors on 12 volts with a chopper board or resistors you can double the speed they would run at if using a 5 volt supply. If you use a 24 volt motor on 24 supply the motors will be slow. Ideal is 5 volts on 24 volt (or higher) supply. This way you can get in to 500 rpm range. With 20 tpi screws that computes to 25" per minute. a 5 volt motor on 5 volt supply gets you about 6".

Titewad,

What are you building your machine from? How large? What powersupply? How many oz-in are those motors? With this info I can get you a ball park speed.

Eric

[Doug Blackmon]

Originally posted by balsaman
No, that is not the issue. Stepper motors are run at a greater than rated voltage to get more speed, and then scheme of current limiting is used to control the current (and heat). If you use 5 volt motors on 12 volts with a chopper board or resistors you can double the speed they would run at if using a 5 volt supply. If you use a 24 volt motor on 24 supply the motors will be slow. Ideal is 5 volts on 24 volt (or higher) supply. This way you can get in to 500 rpm range. With 20 tpi screws that computes to 25" per minute. a 5 volt motor on 5 volt supply gets you about 6".


Eric

Ok so if I understand this correctly you are overdriving the steppers by supplying a higher than rated voltage to them. And you are using the resistors to bear the load to help pervent the stepper from meltdown?

Also what about that E-Stop button you have an extra one to wheel and deal on??

Doug

[balsaman]

Have a look at http://209.41.165.153/stepper/Tutorials/UniTutor.htm

All kinds of info about unipolar motors and current limiting.

Oh- the estop was removed and recycled from an obsolete machine. You should be able to find one like it at a local electrical supplier.

Eric

[Jojje]

At http://www.allelectronics.com/cgi-bin/category.cgi?category=400600&type=store u can find steppers at a good price, or ?

/// Jojje

[kfong]

Hi Doug,

Nice to see this thread pick up. Been busy. Happy New Year everyone. Doug, I'm not familiar with the copiers your talking about, but I assume they are the big office type and have quite a bit of mass to move about. That's why I was interested in your 5 phase motors. 5phase has more steps and are usually found on higher end equipment. All three found on the site you pointed to would work with cranky's setup. I'm really interested if they are the 230oz ones, since that would be perfect for a real mill. As for the 5phase design, we have it done but haven't had the time to verify it completely before we release the boards to the public. This requires some running time, ect. Been too busy with our web site and other projects. Voltage is high on these steppers, but the holding torque is good and I suspect the rotor inertia is better, but need to compare that to an equivalent bipolar motor. Our design won't be cheap to build either, since it requires 5 LMD18245, need one per phase. These are rather expensive chips, at least they are from Digikey. Like I said, these are more complex than the regular steppers to work with.

Do you think you can pack one up and send it to me? My email is kinf@embeddedtronics.com. Go to my website and see if there is something your interested in? Perhaps we can trade. If they are the 230's then you have yourself quite a powerful stepper in a very nice compact package and I would be interested in getting 3 of them. My web site is embeddedtronics.com

Sincerely,

Kin Fong

Originally posted by Doug Blackmon
I would like to be able to tell you more about the motors, but the part numbers on the sticker do not match what is on Oriental Motors web site.

Here is a link to all the 5 Phase motors in the Vexta Series.
http://www.orientalmotor.co.jp/cgi-bin/WebObjects/UPOMStep.woa/wa/F2?frameSize=60&seriesId=5CSK&typeNameId=1

I do know for a fact there 24 volt .72 step single shaft.
with a 2.36 inch Frame

That leaves three to choose from on there site.

Considering this motor is a scanning motor from a Canon imageRunner 330 Digital copier. So if I had to put money on it I would say its 59 oz Holding torque.

Again I have alot of equipment to look through so there is no telling what I may run across.

So let me know what ya think. Also if you have a control design to share using a 5 Phase motor please share. Im sure this could be used.

Doug

[Doug Blackmon]

If you still online check you email..

[xairflyer]

Had my motors turning today, just on the bench connected to the driver board.

The little K179 unipolar driver kit is great as it has it's own speed and direction control so you can experiment without having to connect to the PC.

I know this is'nt much compaired to what some of you guy's have done, but this is the first time I have even seen a stepper turn !!

Now I know all about the windings and how to find the firing order !

[xairflyer]

I while back I posted that I had problems getting a PC PSU working.

Well I am still having problems, I got the ATX supply today to work and never switched it off again just in case.

I am glad I did'nt because when I was finished playing with my motors, I turned it off by disconnecting the green to ground on/off wire, and then tried reconnected it again and it powered up again OK.
But when I switched it off at the mains it would'nt come on again and has'nt since ??

This happened before and I bet if I try it tomorrow it will power up again no problem ??

Anybody got any ideas.

[kfong]

Hi xairflyer,

Some of the older power supplies required a load to come on.
Throw on an old hardrive and see if that helps, floppy drive might work, but that might not draw enough of a load. If it works, then it means it uses a current sensor and you will need to figure out how much current it requires to turn on. Might not be a problem once you have everything online.

Kin Fong

Embeddedtronics.com


Originally posted by xairflyer
I while back I posted that I had problems getting a PC PSU working.

Well I am still having problems, I got the ATX supply today to work and never switched it off again just in case.

I am glad I did'nt because when I was finished playing with my motors, I turned it off by disconnecting the green to ground on/off wire, and then tried reconnected it again and it powered up again OK.
But when I switched it off at the mains it would'nt come on again and has'nt since ??

This happened before and I bet if I try it tomorrow it will power up again no problem ??

Anybody got any ideas.

[kfong]

Doug,
24 volt steppers of any kind are bad news! Keep looking!


John




I don't think that is true, you need to see the motor specs at that voltage level and see if it provides useful torque you need. What I think you really meant is motors with a high winding inductance aren't usually useful since that implies weaker torque specs, which is why they are usually associated with high voltage ratings.

Kin Fong

Embeddedtronics.com


Originally posted by Doug Blackmon
.

Dont make me have to spend money... lol Thats cool, ill just tear some more old copiers apart tommorow..

Doug

[xairflyer]

I have a cd rom drive and a floppy drive connected to it plus a resistor across the 5v.

I switched it on again a half an hour ago and it powered up no problem, switched it off again at the mains and now it won't fire up.

Seems to be OK if I leave it awhile - strange ?

[Doug Blackmon]

Originally posted by xairflyer
I have a cd rom drive and a floppy drive connected to it plus a resistor across the 5v.

I switched it on again a half an hour ago and it powered up no problem, switched it off again at the mains and now it won't fire up.

Seems to be OK if I leave it awhile - strange ?

Is it a ATX 1.0 or 2.0 powersuppy..

Dont know if this will help you or not but here is a document I ran across on the net a few nights ago.

How to Modify an ATX Computer Power Supply

First off a warning about working on AC powered equipment…ALWAYS make SURE the equipment is unplugged! The following shows how I alter a surplus ATX computer power supply to power 12VDC CNC projects. Do this modification at your own risk. Don’t blame us for anything. I’m providing this as a courtesy only!
Materials needed include the ATX power supply rated at least 8A 12VDC, 2pcs 8R 20W resistor (Radio Shack #271-120), tie wraps, and black electricians tape.
Start by removing the cover and separating 3 heavy black wires (common), 1 heavy red wire (+5VDC), the only green wire, and one heavy yellow wire (+12VDC). Now clip all the rest off at about 2-3” from the PCB. Tape the like colored wires together in a bundle. The remaining colored wires can be cut off very short and left alone. Now tape the bundles together. Next step is to trim 1 black and the green wire to about 4”, solder together, tape the joint, and tuck out of the way.
Mount the 2 8R, 20W resistors to any convenient place in front of the fan with the tie wraps. Solder 1 black wire and the red wire to them forming a parallel circuit (resulting in 4 ohms). Fish the remaining black and yellow wires out of the case. Attach the top and your done. Of course you can mount Banana Jacks to the case too!

Below is an example of one I just completed. (Only 1 8R resistor is shown, you’ll get more volts with 2 in parallel) Dave Rigotti





http://home.earthlink.net/~daflea//images/clip_image001.jpg

[balsaman]

It should fire up every time. Get a new one.

Eric

[xairflyer]

I think you are right Balsaman. Annoying thing is it works perfect when powered up, If I leave it for hour or so It fires up no problem.

Great article Doug this will useful to others I bet.

[xairflyer]

I am going to get a new psu but would love to figure out what is wrong with this one.

If I leave it plugged into the mains, and switched off, by removing the green wire from grd (like in a computor) it will fire up every time, and I have tried all day to check.

If I switch off the mains even for a second, it won't fire up again for hours ??

Really weird eh !



Just started building my machine and I have started a thread over on the excellent cnczone site. In case anyone is interested in a mdf machine.

http://www.cnczone.com/showthread.php?s=&threadid=2534

[Doug Blackmon]

How many amps does all the steppers need to operate with the unit is under a load.

I have several powers supplys at work that you will not need to modify other than providing a power switch.

Looks good so far. I will be officialy starting my project in Febuary. I plan on getting a set of Cranks plans to start off.


Doug

[shoutchen]

http://www.hardwaresecrets.com/faqpowersupply.html


take a read of this, maybe it will help...


Steve H

[balsaman]

Originally posted by Doug Blackmon
How many amps does all the steppers need to operate with the unit is under a load.

Doug

Steppers know nothing about the load that is attached to them. They draw thier rated current weather they are running or stalled, stopped, or loaded or not.

If unipolar motors are used the current will be the sum or all the windings rated current, so it's the rated current times 2 times the number of motors (usually 3). For 1 amp motors the PS needs to be 6 amps.

You should be able to get a surplus 12 volt PC supply for $5.00 or so. Get an AT supply if you can.


Eric

[xairflyer]

That's interesting Eric, I always thought people generally recommended the ATX supply.

Going to order a new one anyway, lots of new ones on ebay.

Just would love to know the problem with this one, going to short out all the caps after it's disconnected, as it seems to be something like that.
Yes I know you have to be careful, some of the caps still have a very potent wack stored in them.

[limbo]

Originally posted by balsaman

If unipolar motors are used the current will be the sum or all the windings rated current, so it's the rated current times 2 times the number of motors (usually 3). For 1 amp motors the PS needs to be 6 amps.
Eric

This is only correct for simple drivers with for instance resistors as current limiters. If you use chopper drives the supply current roughly halves when the voltage is doubled, staying at the same energy consumption. It sounds strange, but (for example) supply current can be 1 Amp while output is 3 Amps.

John

[limbo]

btw,

xairflyer, nice setup. Don't you just love MDF? ;)

John

[Doug Blackmon]

Originally posted by limbo
This is only correct for simple drivers with for instance resistors as current limiters. If you use chopper drives the supply current roughly halves when the voltage is doubled, staying at the same energy consumption. It sounds strange, but (for example) supply current can be 1 Amp while output is 3 Amps.

John

Ok,

now im confused lol.

First on how a motor draws curent. I thought in my electronics classes way back when I learned that a motor does not draw its rated amperage unless the motor is under a load.

Also I thought resistors were for limiting voltage not current.
With that in thought I was planning on using a 24 volt 6.3 amp power supply from a copier and stepping the voltage down to 12 volts using resistors. This power supply has the foot print of a smaller ATX PS but is half the height.

I know when there are serveral ways to wire a motor to achive different results.

Forgive me if im wrong I have been reduced to a board swaper working for a Canon Dealer and we rarely ever get to do real electrical troubleshooting. Its mostly mechicanal stuff now that goes wrong.



Also could you guys clear up some of the terms i have been reading.

Chopper Drive?

[limbo]

Doug,

Sorry about that. I never ment to get you confused.

On motor current:
Normal electric motors draw less current at lower load, steppers don't.

On resistors:
With a given supply voltage, putting a resistor in series with your motor-winding will decrease the current. (and also the voltage across that winding.)

On drivers:
Stepper motors have a specified max. current. The max voltage that is often stated comes from multiplying the max. current by the winding-resistance. (So if you simply apply max. voltage at a winding this results in the max. current.)
The only disadvantage here is that the inductance of the coil causes a dwell time for the current to reach max. value, limiting speed. A higher voltage gives shorter dwell time, but you need something to make sure the max. current is not exceeded.

Simple drivers do this by placing a resistor in series with the coil. When voltage is first applied (making a step), there will be low current (due to the dwell), causing low voltage drop across the resistor. Most of the supply voltage will be across the coil giving faster current rise and higher speed. Disadvantage of this method is the power that is wasted in the resistors. High voltages require big supplies because, as balsaman said, the supply current is sum of all winding currents.

More complex drivers (choppers) apply high voltage at the coil and measure when max. current is reached. At that time they switch off for a short time and back on again, untill max current has been reached again, and so on. Think switch-mode power supply. This is much more efficient and suitable for higher voltages and speeds, with reasonably small power supply.

xairflyer found a good deal for the first type, xylotex is a relatively cheap example of the second type.

Looking back this is probably more than you ever wanted to hear, but I feel that now I've caused it I should clear it up...

good luck building your machine,
John

[Doug Blackmon]

Originally posted by limbo
[B]Doug,

Sorry about that. I never ment to get you confused.

On motor current:
Normal electric motors draw less current at lower load, steppers don't.


Ok so I wasnt loosing my mind then, I just had half the answer.


On resistors:
With a given supply voltage, putting a resistor in series with your motor-winding will decrease the current. (and also the voltage across that winding.)


Ok so I must assume if you place a small compactor across the windings of a motor you will incress the starting torq of a motor.
I have seen the pratice on small RC cars. So like I said I assume thats the propose.


On drivers:
Stepper motors have a specified max. current. The max voltage that is often stated comes from multiplying the max. current by the winding-resistance. (So if you simply apply max. voltage at a winding this results in the max. current.)


Ok back to math class If I take a 24 Volt standard DC motor that has a 0.13 Amp rating.

The coil has a resistance of 3.73M so my meter says.

0.13 X 3.73 comes out to 0.4849

If I remember about moving Decmial points that would equal 48.49 Volts

If I did my math right it would seem the motor is rated below its maxium.


Also would I be looking at to much trouble adding resistors to my 24 volt power supplys to drop the voltage to 12 volts.

Dont sweat explaning that. I found it interesting reading, I have allways loved electronics. The problem was when computers came out I found programming and playing games more interesting and lost focus.

Doug

[balsaman]

Originally posted by limbo
This is only correct for simple drivers with for instance resistors as current limiters. If you use chopper drives the supply current roughly halves when the voltage is doubled, staying at the same energy consumption. It sounds strange, but (for example) supply current can be 1 Amp while output is 3 Amps.

John

You are correct.

Eric

[Doug Blackmon]

Originally posted by balsaman
Have a look at http://209.41.165.153/stepper/Tutorials/UniTutor.htm

All kinds of info about unipolar motors and current limiting.

Oh- the estop was removed and recycled from an obsolete machine. You should be able to find one like it at a local electrical supplier.

Eric

Duh,

I guess if I would have read that page a little bit closer I would have had all my questions answered..

"Walk it from the wall"

Doug

[xairflyer]

Went to have a look at my PSU today to see if I could sort it out, and it would'nt fire up at all.
Going to smash it up with a hammer just for the satisfaction. !!!

Ordered a new 300w one yesterday £14.50 incl P & P really cheap when you think of it. Where would you get a 10A 12v supply for that money.

[balsaman]

Please do smash it, we are tired of hearing about it...LOL

Just kidding of course. You are just like me. My motherboard quit, I just can't throw it away because "it looks like it should work fine". I keep hooking it back up and it still doesn't work..:) I hope your new PS works well. :)

Eric

[AdrianM]

I have read most of this thread...whew its long!

I am pretty confident in my ability to build a CNC mill however I am a bit intimidated by the process of turning a cad drawing of a part into an output the mill can work with.

Whats the best way to do it? What soft ware? I use Auto Cad 2004 for simple 2D drawings of plane parts.

[uscra112]

Yah, Adrian. AutoCAD can output a file format that several software packages mentioned in this thread can turn into a cutter path. Keep reading!

[limbo]

Adrian,

You can use yasoft's free ACEconverter to convert DXF to G-code. Very simple, only no radius correction, so you would have to draw your parts slightly bigger to compensate for the width of the router bit.
Another possibility is Deskam. Theres a free (time-limited) demo, and it has radius compensation, graphical interface and a lot more neat options.

greetings,
John

[Doug Blackmon]

John,

Do you have URL's for both pieces of software.

Doug

[DICKEYBIRD]

Here's Ace Converter: http://www.yeagerautomation.com/price.htm 4th from the bottom. Nice piece of software!

[Jojje]

Hi, maybee http://www.cncportal.com can help u.

Or program for Linux ?

It's FREE, FREE, FREE ;-)

[Jojje]

Forget, here is the FREE program for Linux: http://www.linuxcnc.org

And a user: www.sherline.com

[ger21]

Adrian, I'm wwriting an AutoCAD VBA macro to export g-code from polylines. You can get it here: http://www.cnczone.com/showthread.php?s=&threadid=2443

It's a little basic right now, but it works prety good.

Gerry

[AdrianM]

Ok im not so worried about the software now...lol.

Ger21 - will your program allow for the router bit's Kerf. I guess it should cut outside the lines...awat from the parts center...it this correct?

[limbo]

Deskam is located at www.deskam.com/deskam.html
Can't miss it:D

John

[ger21]

If your controller supports tool offsets (G41, G42) Then you can add those in and the controller will handle that. If not, you can just use offset in Acad to offset the lines 1/2 your tool diameter prior to exporting the g-code.
I really just wrote that for myself. I probably won't update it while I try to find time to get my router built. Maybe at that point I'll add more features as needed. I think right now it's fairly usable, though.

Gerry

[shim]

Cranky,
Got my Morph & Piker build instructions. A few questions I have while going through the build instructions.

1. What is the best way to cut the v-channel on the v-blocks.
2. How thick is 18 Guage Aluminum.

Thanks.

-shim

[crankorgan]

Shim,
My support conference is off SUPPORT on my main page. Not here!

Cranky

[shim]

Opps. Sorry about that. Will check at your SUPPORT page.

-shim

[crankorgan]

Guys,
Remember awhile back Zoltar got upset because somebody cloned his machine? On his website he made it a point to pick on Roller Blade Bearings. Now he has a design that uses Roller Blade Bearings and ideas I posted here over a year ago. He claims he is using a French design. But where did the idea for the French design come from? Does a FRENCH Design mean: "A clone of a machine that uses the ideas of John Kleinbauer"
Zoltar! All your designs are clones of other people's stuff. You should be the last to complain! Don't you have any original ideas?


John Conrad Kleinbauer

[uscra112]

Don'tcha just love it Cranky?

Not just here - I was in a meeting with a supplier of automated material handling equpment a few years ago, (managing suppliers of this stuff is one thing I do to earn my crusts), and the guy was claiming that he was planning to patent a flanged roller design he was using. I had to bite my tongue to keep from laughing. He'd picked the roller out of the Reid Tool catalog! ! ! ! (No, no, he wasn't French. .)

Interesting side note - the patent system was instituted so that machine designs could be protected for commercial exploitation by their inventors. The situation that prevailed prior to the patent system was such that any technical innovation had to be kept a deep, dark secret. In a machine tool history book I have they mention that a certain individual in England, at the pre-dawn of the Industrial Revolution, had a turning machine (or was it a screw cutting machine?) that had revolutionary (for then) performance. But because only two or three individuals were ever even allowed to SEE it, there is today NO knowledge of how it was made or how it worked.

Cranky, we are all copying each other! That's what lets us drive innovation at such a breakneck pace.

Another story - I was aquainted with the president of a software company in Cambridge many years ago. He had developed software that managed critical-path scheduling for big projects like the Alaska pipeline. I asked him how he patented it. He said they didn't even try. They competed by innovating faster than everybody else!

[crankorgan]

What got me is he made fun of the Roller Blade Bearings on his website even though people here were getting results using them. The idea of using Roller Blade Bearings blolted to angle with an offset came from my design and this website.
This is the top thread on building a homemade CNC anywhere on the net. Others have read this thread and carried the info to other areas. They have even stolen some of the pictures from here.
It's one thing to borrow some ideas, but to threaten someone and then turn around and do the same thing is wrong. He thinks he owns what he borrows.

[uscra112]

I knew a guy like that, once. Friend of mine told me never to let him in my shop, because as soon as he saw something he wanted, it took him only a few seconds to convince himself that it actually was already his, and he should take it back from me. I suppose evolution has a use for that kind of behaviour somewhere, sometime, somehow. I at least try to give credit when I swipe somebody's idea. I suppose that's why I don't have V.P. Engineering next to my name.

[crankorgan]

I just went back through the thread! It's all here. His negative comments and all. The most he ever offered was a picture of his motor coupler. Even a foam cutter is here for him to copy.

[AirX]

Zoltar has already removed all the links to his pages, cant find a link anywhere that works.

Cheers,

Eric B.

Ok, he changed them all... :rolleyes:

[balsaman]

http://www.rcmodels.net/cnc/

Eric

[oz9ny]

Hi

Ideas come up from time to time!

Back in 1980 I made a tangential árm for a recordplayer. Basic principle was from an article in "Wireless World".
I didn't hve access to an advanced machine-shop at the moment so I developed a small carriage using very small ballbearings (6mm diam.) as wheels, then I used some teflon blocks to guide the wagon and keep it rolling on the track.

The record player is gone now but I may keep some photos somewhere in my archives. I'll try to find them :-)

/Niels
PS: I know that Cranky has given some nice ideas to the hobby CNC community and the web has been his medium. But take a tour in the pre web paper litterature and get inspired or amazed.

[uscra112]

Invention is one thing - exploitation of invention is quite another.

I'm still bothered by people who think that big money should just fall in their lap as a reult of some clever idea they've had. Rarely if ever. What makes the money is the IMPLEMENTATION and SALE TO THE CONSUMER of the idea. Investment of capital is what makes inventions make money. Cranky's investing most of his time and effort in this.

The game of deciding who had the idea first is best left to the college professors. Primacy of ideas IS their stock in trade. Makes for some wierd ideas, sometimes.

I still have my old Rabco turntable with the tangential arm. Pain in the keester, it is! But I like it anyway, because it's so strange.