when I try to compile the reprap arduino firmware 1.3 I got this:

error: 'char word [128]' redeclared as different kind of symbol

what do I have to do ?

I have a couple of questions about the construction of the linear motion sets:

http://www.contraptor.org/linear-rails-bearings-subset
It says the rails use drill rod. Does that mean they have a thread? If yes, what for? Or is my understanding of English wrong, and a drill rod is a rod with a smooth surface?

http://www.contraptor.org/basics#toc5
About the linear rails and ball bearings it says that the bearings are side loaded. Is that an engineering term which expresses that the bearings are fully on the rails, but a bit sideways? Is this design due to the fact that the slide can only move along one axis?

http://www.contraptor.org/make-shaft-mount
The current design of shaft mounts uses screws to put the bearing in place. Why did'nt you simply drill a bigger hole in the angle and press the bearing inside?

Thanks,
Markus

I started to prototype some angles using ponoko.com in order to create my own metric version of contraptor. My aim is to progress slowly as I am not so much an mechanical guy and I still need to figure out how some of the slinding elements, motor couplings, pulleys and rails work together.

My first batch of laser cut angles can be seen here: http://justjoheinz.posterous.com/contraptor-teile It is just a small prototype production.

MY next attempt will be to create linear motion kits and go large scale in the cutting of angles of bigger sizes. The acrylic parts seem to be reasonably stable. Of course they would not match the aluminium angles, but I guess it should be doable to construct e.g. the X-Y plotter.

I would be delighted if others respond to this thread if there still exists interest in the metric version of contraptor. As I am not limited to exisiting aluminium profiles sizes, I can pretty much lasercut anything, as long as it is 3mm thick. So currently I try to design something which adheres to the grid style of contraptor, as I have not really found matching elements in metric versions of alumunium profiles, which would allow this.

I recently stumpled upon the contraptor site and love the idea of it. Since I live in Europe I would be looking into the metric contraptor and hope that it is still alive and kicking and making progress.

Whilst I was thinking how I could acquire all the parts, I wondered if it is not possible to create a super mini cnc, which solves the only task of drilling the holes into say a 1m beam of the aluminium profiles. The meter could then be cut manually. That way one could basically bootstrap building parts of the complete kit, e.g. for building the CNC contraptor and one would require to purchase only a minimum set of new elements.

When the material to be drilled is only the beams of profiles, it would save an axis and make the bootstrap CNC machine easier and simpler to build, wouldn't it? I'd love to hear from you,

Markus

I used ball bearings instead of the plastic channel.

Each sliding element is powered by a belt (like the XY Plotter). Each sliding element has 4 bearings. Three to ride the angle frame and one for lateral stability. The three that ride the frame are two above and one below with an adjustable spacing.

It seems to work really well.

After I mount the pulleys, shafts and belts, I'll report back.

One of the suggested methods is "Using corner jig". Can someone tell me how to do that? I don't have any peg board and I'd like to get a few holes drilled.

Thanks in advance…

I want to build a contraptor cnc, and for now I am gathering the best components list, and starting for the motors and looking at this list I don't know what is the best nema23 to choose, looking for your best advice on this

thank you in advance

The U channel seems sort of tricky to get (I'll obviously break down and put in an order for it a McMaster if I can't find it locally). Is there another name for it or other materials that work?

Second, what is the experience with longevity. My intuition is suggesting that the sliding elements might need a lot of adjustment. Any reports on that?

Either way, I'll very likely use them on my first Contraptor since they clearly are simple and inexpensive.

http://sdp-si.com/eStore/PartDetail.asp?Opener=Group&PartID=29443&GroupID=218#

They are out of stock!

What to do? I was clicking around in http://www.mcmaster.com but I'm a little unsure as there are a lot of parameters involved. Is this pulley in McMaster?

Darcy

1) Given the contraptor 10 tooth pulleys, is the the forumla to get from shaft distance to belt size [Shaft Distance" * 2] + 2" = belt size. So if you need 100 inches between your shafts, then the belt size is XL202? Or if you want 30" between shafts, then it's XL600? Does this seem right?

2) Is buying a bunch of open ended belt a good idea? Then we could support any contraptor shaft distance. I was thinking of this since belt sizes are not all even. At least with SPI and McMaster, not all shaft sizes (ones that are contraptor compatible) are supported.

Any comments?

I just received my mini-cnc subset ( thanks a lot ! ), and I'll try logging thing here as I build it.

You can find all the pictures also on Flickr: http://www.flickr.com/photos/arthurwolf/sets/72157623876165406/
And the videos also on Youtube : http://www.youtube.com/user/chenillonage

About the build, I'll build the miniCNC itself the exact way it is supposed to, but as I already have the electronics/motor, I'll use what I have, that is :
- 3 x Pololu Stepper motor driver , 2A, 35V, Bipolar, 16 steps microstepping -> 12,95$ each
- 3 x 5718X-01E Alltronics bipolar stepper motor, nema23, 200 steps, 2A -> 9,95 each
- 1 x Arduino pro mini :  18.95$

Day 1.

Here = Spain, so it took like a week to ship.
It came as two shipments, a tube for the long parts and a box for the rest.
Nothing's missing, and everything is shinny and looks very cool.

Picture of the package's content :

Same thing, but with tape removed :

So then I went online to http://www.contraptor.org/mini-cnc-subset, and started following instructions.

For each part type I assembled, I recorded the last one I assembled and put it on Youtube.
I had problems with finding a good spot for the camera, but then I realized I had tons of contraptor nearby :)
So I made this camera stand wich worked perfectly :

On this first day I assembled all components for which a detailed step by step instruction is available on the Wiki, namely :

• Captive nut
• Shaft mount
• Coupling nut clamp
• Belt clamp
• Sliding elements
• Linear bearings
• Linear rails

The assembly of the components was very easy, very fun, and took less long than I expected.
The only difficulty was with the Coupling nut clamp, the notches were not deep enough so I had to make them deeper, did not have the right tools, cut myself, but now it all fits good.

Here are the videos for each of the 7 different component types :

Pictures of the finished components :

Linear rails :

Linear bearings :

Captive nut, Belt clamp, Shaft mount : 

Sliding elements :

Day 2

So now I'm in no-documentation territory, the real fun begins.
Well that's not completely true, there are lots of good pictures of the different steps, that should count as documentation.

Today I assembled/filmed the assembly of the base, the y-axis rail, and the x-axis rail and wagon.
Nothing much to be noted, except that you really really want to follow the instructions right.
On day one for the linear bearing elements, I did not follow the part where you have to exactly ajust to 1/8", and today it caused me a lot of trouble when making the x-axis.

Assembly of the y-axis rail :

Assembly of the base subassembly, made 3 videos, one for the back, one for the front, and one for joining them.

The x axis rail : 

The x axis stage :

Now pictures of each finished subassembly :

Y-axis rail subassembly :

Base subassembly :

X-axis rail and stage subassembly :

Day 3.

Bad surprise today, flickr does not want more pictures, have to wait until next month … so no pictures.

Everytime I post a video, Albanetc checks it and give me tons of precisions and cool advices, it helps a lot. I try getting the more of that as I can into the video annotations. OSH things rock !

So today I attached the Y-axis to the base, and made the Z-axis.
Just following the pictures, simple, a few things to figure out, but nothing hard.

Here are the videos :

Y-axis to base subassembly :

Z-axis, 4 parts : 

Will make more when have time.
Thanks for reading.

_{TODO: Make video to explain the 1/8" thing with the linear bearings
TODO: Add youtube's subtitle thing to the video where it can help understand}

I assembled my Mini CNC and I'm looking forward for making some controlles GCode movements. Until now it moves, but not as I expect.

First of all a descripion of my environment with some specifications.

Hardware

• Arduino Board Duemilanove with Atmega328
• Reprap Stepper Motor Driver v1.2
• Mini CNC with threaded-rods 1/4-20
• Alltronics #44A501711 NEMA23 motors

Unipolar stepper motor. This motor is a NEMA size 23. Specs are 60 in/oz Holding Torque, 200 steps/rev, 2.3V, 2.3A, DC, 80 C degree Rise

Software, Firmware

• IDE Arduino 0018, Linux 64bit
• Arduino Firmware v1.3

According to the explanations on Arduino G-Code Interpreter I'm using the following settings in the file _init.pde

 // define the parameters of our machine. #define X_STEPS_PER_INCH 4000 // 200 steps/rev + 20 threads per inch * steps in a revolution #define X_STEPS_PER_MM 157.480315 // *_STEPS_PER_INCH / 25.4 #define X_MOTOR_STEPS 200 // to double because of half stepping? X_STEPS_PER_INCH also? #define Y_STEPS_PER_INCH 4000 #define Y_STEPS_PER_MM 157,480315 #define Y_MOTOR_STEPS 200  #define Z_STEPS_PER_INCH 4000 #define Z_STEPS_PER_MM 157,480315 #define Z_MOTOR_STEPS 200 //our maximum feedrates #define FAST_XY_FEEDRATE 1200.0 // just a assumption #define FAST_Z_FEEDRATE 1200.0 // just a assumption // Units in curve section #define CURVE_SECTION_INCHES 0.019685 #define CURVE_SECTION_MM 0.5 // Set to one if sensor outputs inverting (ie: 1 means open, 0 means closed) // RepRap opto endstops are *not* inverting. #define SENSORS_INVERTING 0 // How many temperature samples to take. each sample takes about 100 usecs. #define TEMPERATURE_SAMPLES 5 /**************************************************************************************** * digital i/o pin assignment * * this uses the undocumented feature of Arduino - pins 14-19 correspond to analog 0-5 ****************************************************************************************/ //cartesian bot pins, settings for Contraptor wiring #define X_STEP_PIN 3 #define X_DIR_PIN 4 #define X_ENABLE_PIN 5 #define X_MIN_PIN 6 #define X_MAX_PIN 7 #define Y_STEP_PIN 8 #define Y_DIR_PIN 9 #define Y_ENABLE_PIN 10 #define Y_MIN_PIN 11 #define Y_MAX_PIN 12 #define Z_STEP_PIN 14 #define Z_DIR_PIN 15 #define Z_ENABLE_PIN 16 #define Z_MIN_PIN 17 #define Z_MAX_PIN 18 // I kicked off the extruder stuff 

If I use these GCode commands

 G3 X0 Y0 I1 J0 F10 

the Mini CNC just makes very little movements, but not movements you can see here for example . I also doubled the values for *_STEPS_PER_INCH, *_STEPS_PER_MM and *_MOTOR_STEPS without any success.

Where is my shortcoming?

Please help!

Christoph

Opened up the jig after drilling one 4' length:

Small error in X (about 0.03", we didn't zero the head properly):

The angle looks pretty good and might require no countersinking which would be a huge time saver:

The holes were not exactly drilled, but cut with 1/4" spiral O-flute carbide router bit for aluminum: http://www.amanatool.com/cncroutingdetails/aluminum-cnc-spiral-bit-51402.html. We started out at about 10 IPM for Z down feedrate and quickly dropped it to 5 IPM, then to one pecking cycle and then to about 1 IPM.

We still have the following problems to solve:

• Even though the channels seem to be tight, the angle moves lengthwise in the channels. This should be easily fixed by adding some restraints at one end of the channels.
• There is noticeable vibration in the gantry and Z stage when it's over the middle part of the jig. This might be more difficult to solve.