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Jan 25, 2006, 02:09 AM
I do my crosswords in pen
I don't know if this belongs in this forum, but where are you guys getting your MM2001 boards from?

Thanks,
Mike
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Jan 25, 2006, 09:30 AM
Registered User
Motoryder,

I purchased a couple of MM2001 board kits from James Leverton (company named The Right Choice) in Arizona. I'm not certain if he is still in business as I can not find a website for him anymore. The kits came with all of the components and professionally etched boards. The boards work great when I hooked them up to stepper motors (I still need to build the mechanics for the foam cutter and a router). His price was much lower than any other supplier I found.

Bob Fox
Jan 25, 2006, 04:53 PM
kak8
I have build my card. There`s a good instruction on the french homepage, part list etc.
I don`t know much about electronics, but my head and hands are ok
The most difficult thing was to find the parts, and make the PCB layout.
Jan 25, 2006, 09:51 PM
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Foam cutting process.


This may be basic for some of you but I feel the Nubies will benefit from an explanation of what we are doing.

Foam comes in many formulations. The most commonly recognized foam is often refered to as styrofoam (kind of like saying Zerox for a copier). Expanded Polystyrene or EPS foam was market by Dow chemicals. It is made up of beads of Styrene that is fused together using steam and a few other chemicals (isobutylene) that are unimportant to the discussion. Note styrofoam also came in an extruded form also well. EPS is usually white in color and can vary greatly in density.

Extruded polystyrene made by DOW under the Styrofoam brand is Blue in color and it presents a much smoother surface due to the smaller sized bubbles in the material. This foam is commonly used in new construction to insulate concrete. We use it for glider wings.

Owens Corning makes a pink extruded foam under the brand name Foamular name. The two extruded foams are mostly interchangable. However differences in weights, densities and composition can be factors to consider.

There is also a gray extruded foam and a white extruded foam (spyderfoam).

EPP or Expanded Polypropelene is the foam used in many flying wings and 3D ship. EPP is a small cell foam which bounces, bends and twist. It is heavier than all the other foams but great for shock absorbing. It is routinely used in sporting helmets. EPP requires a much different cutting technique than the other foams because it tends to remelt to itself.

Many of these foams can be found in Lowes and Home depot. EPP is usually only available at major foam distributors. If you live in a large city in a cold area of the country, you can probably find many or all of these foams available from a foam insulation company. Check your Yellow pages under Insulation. If they don't have what you are looking for call a large contractor and ask him if he can point you in the right direction. Be prepared to spend some serious money on foam. Most insulation places are used to selling by the pallet. If you make friends with the folks on the loading docks you might be able to buy broken pieces....... Coffee and donuts can go a long way.

All of these foams can be cut with a variety of hand tools or a hotwire. Since this is an article about hotwire cutting we will stick to that. A hot wire is a monofilament wire usually stainless steel,
Iconnel wire http://webpages.charter.net/mnemesh/, or nichrome which is hooked up to DC current to heat the wire. The wire is kept stretched tightly between two points under tension. The French sites refer to the cutting wire as a guilletine. The cutting wire can be suspended on a bow or mounted directly to the towers with a spring.

When the wire is heated and comes into contact with foam a portion of the foam melts away and as the wire moves through the foam the pattern is created.

There are two schools of though on how foam should be cut. Contact cutting and radiant cutting. In contact cutting the hotwire is heated just enough to pass through the foam with a minimum kerf. This produces very smooth cores but is slow going.

Radiant cutting heats up the cutting wire to the point that the foam melts away before it can come into contact with the wire. Although this is a faster way to cut, much more care must be taken to ensure the wire doesn't dwell in one spot and thus create a major divot around the wire. Radiant cutting also produces smooth cores.

Here is an example of a part cut with the CNC cutter.
Last edited by bgriggs; Jan 25, 2006 at 10:29 PM.
Jan 25, 2006, 09:58 PM
I do my crosswords in pen
Cool, thanks for the info ninpofox and kak.
Jan 25, 2006, 11:32 PM
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Tomorrow CNC Machines


Tommorrow CNC machines and then on to step 2. Hopefully we will get to the actual software quickly.

Please let me know if my pace is too slow or the information I am providing could be improved. Please be specific.

Bill
Jan 26, 2006, 09:26 AM
Embrace the suck
nauga's Avatar
Quote:
Originally Posted by bgriggs
Please let me know if my pace is too slow or the information I am providing could be improved. Please be specific.
Speaking as a newbie to CNC, it's all great, thanks for putting it together. I've got a HobbyCNC board in the box waiting to be assembled, and was planning on using GMFC, but I'll see what you have to say before making a decision. Just a general comment, there seems to be plenty of advice in the archives about using the software, what I'm interested in but don't seem to find is clear guidance on the initial setup, like drivers, installation, and getting the software to 'play nice' with the board the first time through. This is not specific to any software/hardware combination.

Nauga,
approaching the cutting edge.
Jan 26, 2006, 11:31 AM
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Quote:
Originally Posted by nauga
Speaking as a newbie to CNC, it's all great, thanks for putting it together. I've got a HobbyCNC board in the box waiting to be assembled, and was planning on using GMFC, but I'll see what you have to say before making a decision. Just a general comment, there seems to be plenty of advice in the archives about using the software, what I'm interested in but don't seem to find is clear guidance on the initial setup, like drivers, installation, and getting the software to 'play nice' with the board the first time through. This is not specific to any software/hardware combination.

Nauga,
approaching the cutting edge.
I will try and include actual setups I use on my machine, however, no two machines are exactly alike.... I will cover the HobbyCNC 4AUPC board with separate heat control. I will also cover the MM2001 board. I don't own the C4 board that CeNeCe makes. I don't think it is fair to ask them to provide one since they have already graciously donated their software. Perhap I can get one of the authors to provide setup info on their board... Also in the FAQ section on CeNeCe website, there is a photo of the setup screen for the MM2001 controller. We are looking into a similar screen for the HobbyCNC controller.

Sites mentioned above:
http://www.hobbycnc.com/driverboards/driverboards.htm
http://www.cenece.com
http://www.cenece.com/cenecepro/faqimages/mm2001t.jpg
http://www.teaser.fr/~abrea/cncnet/e...2001/mmx.phtml

Bill
Jan 26, 2006, 01:47 PM
Registered User
dionnel's Avatar
Quote:
Originally Posted by bgriggs
EPP or Expanded Polypropelene is the foam used in many flying wings and 3D ship. EPP is a small cell foam which bounces, bends and twist. It is heavier than all the other foams but great for shock absorbing. It is routinely used in sporting helmets. EPP requires a much different cutting technique than the other foams because it tends to remelt to itself.

The French sites refer to the cutting wire as a guilletine. The cutting wire can be suspended on a bow or mounted directly to the towers with a spring.

Hello Bill,
How are you old gangster!!?
Oops, sorry, you're on the other side.

Good work so far on that thread !

For those who do not know me, I'm a French Canadian living in a bilingual area (the capital). With a friend living in Montreal, we built 2 CNC foam cutters a few years back and are both using GMFC Pro.

Being French, I can correct you, Bill.
Guillotine is the word.

It will be interesting to read the evaluation and comments from all.

More about what I did.
I etched our MM2001 boards, bought the electronic parts mostly from www.digikey.com, assembled the electronics, etc, while Mark - my Montreal buddy did the mechanical part (sliders etc).
The Fet to control the heat came from an electric speed controller.

We've been cutting a lot of wings (gliders for Mark, DLG for both of us), but I also have been cutting fuselage parts from CAD info. Initally using AutoLisp functions I wrote and GMFC Pro has now incorporated DXF file input and is getting better and better at the none wing related work.

I buy my Extruded and Expanded Polystyrene at the local Hardware store (Rona Hardware) and then go to the Quebec side and a bigger contruction store to get higher density Extruded foam (similar to High Load 60).

I got my EPP direct from the manufacturer.
There is a foam manufacturer outside Montreal that forms various type of foam pellets and boards including EPP (in black and in white) - Polyform is the name of the company.
I have not experienced a lot of problems with the EPP soldering itself back together in the hot cutting process. I'm much more concerned about EPP fumes.

I had much more problems with the soft padding foam (neoprene foam) used in blocks to pad your car when putting a canoe/kayak on top. Usually grey color and available at any outdoor outfitter store. This neoprene is gluing itself back like crazy. If anyone has worked with this successfully, I'd be hapyy to know how.

For wings, I use mostly Extruded blue.
For shapes, I prefer to use higher density Expanded polystyrene.
The process for Extruded foam is roughly to press the raw styrene through a steel mouth of rectangular shape just like you do with toothpaste. The raw styrene has been heated and pressured out like the toothpaste, but as it is coming out, it also cools down and solidifies. The outside of the block cools down faster and the overall result is that there is a lot of internal stress built in your slab of Extruded foam. Make a cut to slice out the top 1/4" of a Dow 2" Blue foam slab and you will end with a nicely curled sheet. The amount of stress seems to varies with the foam batches.

Expanded foams do not have that internal stress. The orignal small beads of styrene are sent into a big rectangular bucket and hot steam send in to expand those tiny beads. The density is a matter of how much original material is dropped into the bucket at first - OK, over-simplification, but enough to get the picture.

Your typical white foam beaded Expanded foam is about 1lb/cu.ft.
I now use locally available white with a blue tint Expanded styrene and another one at around 1.5 and 2lb/cu.ft. for anything with good effect.

When you buy your foam, be sure it is not recycled.
The recycled one with have impurities that will disrupt the even motion of the hot wire and make dents.

One thing I'd like to see here is how people are handling cases of severe taper. GMFC is doing well until the taper ratio reaches 2:1. The wire being of the same temperature across it's length will move slower on the short chord side and have more time to melt the foam. With GMFC, with a taper close or above 2:1, it is difficult to have a temperature that will cut without any hair on the big side and a smaller tip that is not overheated.

Anyway, that's it for now.
Looking forward to learn a lot here.
Ciao!

P.S. Bill, I'll see you again in Kingston ?

Louis
in Ottawa, where the foam is used not just to keep the frost outside.
Last edited by dionnel; Jan 27, 2006 at 10:06 AM.
Jan 26, 2006, 08:54 PM
Embrace the suck
nauga's Avatar
Quote:
Originally Posted by bgriggs
I will cover the HobbyCNC 4AUPC board with separate heat control. I will also cover the MM2001 board.
Ah, so maybe I should ask my question directly. I've got a 4AUPCWHC ('with heat control') sitting in pieces in the next room. I figure it's about time to solder it up and see if I can keep the magic smoke in. I've installed GMFCpro for evaluation and it looks like it will do what I need.

My question, at least for now, regards the software driver. GMCF refers to installing the MM2001 driver. Is this the driver needed for a 4AUPC as well or am I missing something? I've scoured the Yahoo groups for CNC foamcutters and HobbyCNC and can't find anything - the response time seems better here so I haven't asked there yet.

...and with that I'll save the specifics for another thread. This thread is a great idea, sorry for the distraction.

Nauga,
who wonders if a wood might be more appropriate
Last edited by nauga; Jan 26, 2006 at 09:07 PM. Reason: Back on topic, Nauga
Jan 26, 2006, 10:22 PM
Make something. Anything!
bgriggs's Avatar
Quote:
Originally Posted by dionnel
Hello Bill,
How are you old gangster!!?
Oops, sorry, you're on the other side.

Good work so far on that thread !

For those who do not know me, I'm a French Canadian living in a bilingual area (the capital). With a friend living in Montreal, we built 2 CNC foam cutters a few years back and are both using GMFC Pro.

Being French, I can correct you, Bill.
Guillotine is the word.

It will be interesting to read the evaluation and comments from all.

One thing I'd like to see here is how people are handling cases of severe taper. GMFC is doing well until the taper ratio reaches 2:1. The wire being of the same temperature across it's length will move slower on the short chord side and have more time to melt the foam. With GMFC, with a taper close or above 2:1, it is difficult to have a temperature that will cut without any hair on the big side and a smaller tip that is not overheated.

Anyway, that's it for now.
Looking forward to learn a lot here.
Ciao!

P.S. Bill, I'll see you again in Kingston ?

Louis
in Ottawa, where the foam is used not just to keep the frost outside.
Louis,

Good to hear from you. I do plan to be in Kingston Ontario for the Fun fly if I can get across the border. Something about not letting undesireables into Canada.......

I'm happy you gave more details on foam because I was really glossing over it in order to get to the software...... I intended to go into much greater detail in the booklet.

Bill
Jan 26, 2006, 11:07 PM
Make something. Anything!
bgriggs's Avatar
Sorry for the lack of new posts today. My car died this week and today I made a deal for a new (to me) one. You all know how long the car dealers like to drag these things out.

Hopefully tomorrow will be a double subject day.


Bill
Jan 27, 2006, 06:06 PM
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bgriggs's Avatar
I now have a C4 controller on it's way to me. Should'nt take long from Spain.

Quote:
Originally Posted by bgriggs
I will try and include actual setups I use on my machine, however, no two machines are exactly alike.... I will cover the HobbyCNC 4AUPC board with separate heat control. I will also cover the MM2001 board. I don't own the C4 board that CeNeCe makes. I don't think it is fair to ask them to provide one since they have already graciously donated their software. Perhap I can get one of the authors to provide setup info on their board... Also in the FAQ section on CeNeCe website, there is a photo of the setup screen for the MM2001 controller. We are looking into a similar screen for the HobbyCNC controller.

Sites mentioned above:
http://www.hobbycnc.com/driverboards/driverboards.htm
http://www.cenece.com
http://www.cenece.com/cenecepro/faqimages/mm2001t.jpg
http://www.teaser.fr/~abrea/cncnet/e...2001/mmx.phtml

Bill
Jan 27, 2006, 10:58 PM
Registered User
The subject of foams is one for some long discussions more on the building side. There is some decent data out there on the more "common" foams used for models.

http://groups.yahoo.com/group/Allegr...s/Skin_Stress/
https://www.rcgroups.com/forums/arch.../t-179292.html

You are most likely to find Foamular 150 and 250 or Dow Blueboard variations at home centers.
The higher density Foamular 400, or 600 or Dow Highload is more of a roofing product. Talk to the guys putting a new flat roof on somewhere to get a sheet.
Jan 27, 2006, 11:20 PM
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Stepper motors


C.N.C. stands for Computerized Numerical Control. Wikopedia defines C.N.C. as follows:

The abbreviation CNC stands for Computer(ized) Numerical(ly) Control(led), and refers specifically to the computer control of machine tools for the purpose of (repeatedly) manufacturing complex parts in metal as well as other materials, using a program written in a notation conforming to the EIA-274-D standard and commonly called G-code. CNC was developed in the late 1940s and early 1950s by the MIT Servomechanisms Laboratory. CNC machines were relatively briefly preceded by the less advanced NC, or Numerical(ly) Control(led), machines

http://www.answers.com/topic/cnc

Basically the parallel port of a computer is used to send/receive bits to a special control board. These bits are translated by the board which then passes the bits along to a special kinds of electric motor known as stepper or stepping motors, which causes them to move (over simplification, but more detail follows). Depending on the order in which the bits are received, the stepper motor will rotate either counter-clockwise or clockwise. When these stepper motors are hooked up mechanically to belts , pullies, screw or slides, they can provide precise movement that is repeatable.

Stepper motors come in two types, Unipolar (the kind we use) and Bipolar. Inside of a stepper motor are magnets. A North /South pole pair constitues a "phase". A "winding" of wire is associated with each "phase". We will use the term "phase" when classifying motors (example 2 phase, 4 phase etc.) and the term "winding" when refering to the wire wound on the poles of the motor.

HobbyCNC 4AUPC stepper control, the MM2001, and the CeNeCe C4 controllers all are known as UNIPOLAR controllers. What this means is that they will all drive a Unipolar stepper motor. A Unipolar stepper motor usually has 4 phases and either 5, 6 or 8 wires. This is the easiest way to recognize a Unipolar motor. Stepper motors are frequently for sale on EBAY. If there is a picture of the motor shown, be sure to count the number of wires displayed and check that you are getting Unipolar motors before you buy.

The Stepdance control from Holland is a Bipolar stepper drive. It uses 4 wire, 2 phase stepper motors and it will not work with Unipolar motors. The Hobbycnc, mm2001 and C4 controller won't work with Bipolar motors.

Getting back to the bits;

When the bits are translated by the controller an electrical charge is sent along the wire to the "windings" The winding will either be turned on or not turned on. When these windings are turned off and on, in a particular order, the motor shaft spins or holds still and can't be easily budged. All of the software we will be discussing translates the drawing we provide through the DAT format and sends the proper signals to cause the motors to move in just the right way to create the shape we are cutting.

Stepper motors are often described by the word NEMA followed by a number (example Nema 23). N.E.M.A. - National Electrical Manufacturer's Association, established standards for motor based on the shaft and face configuration and the dimensions. This standarization allows us to purchase motors from a variety of sources and have a guaranteed fit. However, always measure the bolt hole pattern yourself.....

Typically Nema 17 motors have a 5mm shaft (.197") diameter, a bolt hole spacing 1.22" and a face size of 1.65"x1.65".

Nema 23 motors have a .25" shaft diameter, a bolt hole spacing 1.856", a face spacing of 2.22"x2.22" and usually have a 1.5" BOSS around the shaft.

You can usually find surplus stepper motors on ebay and electronics surplus stores. Make sure you know what you are buying. Similar sized motors can vary quite a bit in torque.
Last edited by bgriggs; Jan 29, 2006 at 10:44 PM. Reason: change title


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