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Idea to pen inlay: CNC software steps

Jimjam66

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This is mostly on request from George, some others might find it interesting. The discussion started in this thread, the pen is a result of the steps shown below:

1. The Idea

I wanted a 'jigsaw' look, as the idea came from the Laserlinez/Kallenshaan jigsaw puzzle kits. I had nothing so heroic in mind - just a couple of pieces which fit into a matching recess in a pen blank. First I found something useable on the interweb:

jigsaw1.jpg

I saved the file (this one was an SVG which was nice but any old graphic file will do) on my HDD.

2. Create the 'Look'

Now I opened it in Inkscape in order to create the look and feel of the pieces I wanted. Inkscape is free, which is a large part (about 99.9%) of the reason I use it, but if you happen to have Adobe Illustrator (over £700 a license if memory serves) it will work just as well. Photoshop will NOT work so well, as it does not create scalable vector graphics (SVG) - important when you start mucking around with the size of the pieces.

jigsaw2.jpg

You can figure that I needed to make the piece into two pieces with a matching side, and I needed an outline of both pieces together for the recess. I also decided to flatten the bottom just because ... :whistling:

Finally I saved it as a DXF file (only recognises lines and curves - doesn't see 'substance').

3. The Machining Sequence

I opened the DXF file in CamBam, where I selected the cutting sequence, the positioning of the pieces relative to the stock, the size, RPM and feedrate of the bit through the material, etc etc.

jigsaw3.jpg

Once that was done I saved a few G-code files out of CamBam which I took to ther workshop to run on the CNC nachine. The G-code files are long lists of machine instructions which the CNC controller machine will use to tell the mill to lower the bit so many mm's, move in a straight line from this coordinate to that one, then execute a curve of this radius etc etc.

A sample of a G-code file follows:

( Made using CamBam - CamBam CNC Software )
( jigsaw pieces inlay 7/14/2013 4:16:49 PM )
( T8 : 0.8 )
G21 G90 G64 G40
G0 Z3.0
( T8 : 0.8 )
T8 M6
( Profile1 )
G17
M3 S18000
G0 X3.1241 Y3.8559
G0 Z1.0
G1 F300.0 Z-3.0
G2 F65.0 X3.1231 Y3.8511 I-0.3653 J0.0713
G1 X3.104 Y3.7633
G2 X3.0082 Y3.4589 I-4.5755 J1.2733
G3 X3.0061 Y3.4528 I0.3773 J-0.1329
G1 X2.9496 Y3.2837
G3 X2.8918 Y3.0866 I2.4233 J-0.8167
G1 X2.8402 Y2.9016
G1 X2.7974 Y2.7609
G1 X2.7808 Y2.7067


4. General

There are CAM software products out there that will let you combine steps 2 and 3, eg. ArtCAM. I've never used them, and once you've checked out the license costs you probably won't either. There are also alternatives to Mach3 (the software running on the CNC controller machine), but Mach3 does all I need. Mach3 will handle a lasercutter/engraver, too, so when I get my laser up and running I won't need another license.

Others may do this differently, I don't claim to have the final solution. This works for me, though ...
 

Jim

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I read this and pretended that i knew what it was all about cos the wife is sat beside me on her computer ... :whistling: I wish i had the time and patience to go out and learn something like this, so respect David and thanks for adding it ... :kiss:
 

clumsysod

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Brilliant what a great explanation. Thank you so much for that.
I had never used a computer until a few moths ago but I do learn quickly and simply marvel at the wonders of modern technology.
I do read plenty and like to educate myself, I have been doing some reading on this subject and beginning to understand the logic of it.
I have no desire to learn CAD that looks a formidable utility but rather than draw my own I can now see how an existing picture imported into the program and then manipulated works so with practice the software could be mastered.
Now the hardware side of it, from what I have read so far I have to raid the office printer plotters for the stepper motors.
There is plenty of threaded stud lying around the workshops at various places I visit, chat the ops guys to find out where I can purloin a controller board and I'll be making something in the morning.
If only dreams would come true.
 

rowdyyates115

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Brilliant explanation, Out of curiosity I am even going to have a bash at the process apart from the actual cnc bit.
What version of CamBam do you recommend?
This has started the design juices again....loving everything connected with turning....

:ciggrin:
Thanks
 

clumsysod

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Controversy.
The boffins have built an old computer with EMC2 running python scripts we can simulate the whole process.
Qcad, f-engrave. I am told that's all i need, playing with it right now.
They have gone hunting for materials to make a table.
7 men working on this project, hope the guvner don't find out.
 

Jimjam66

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Controversy.
The boffins have built an old computer with EMC2 running python scripts we can simulate the whole process.
Qcad, f-engrave. I am told that's all i need, playing with it right now.
They have gone hunting for materials to make a table.
7 men working on this project, hope the guvner don't find out.

EMC2 gets good feedback considering its freeware, but I've never used it as i dont have Linux. You might want to point your team to Build Your CNC for ideas and advice. Shout if I can help with anything.

Build Your CNC have this tutorial on EMC2 ... With a bootable DVD download running Ubuntu so you can just put it into your Windows machine and reboot. Genius!
 

clumsysod

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Thats a couple of great links David and yes I can see those screens in the tutorial and change the settings and learn how to configure it.
But I fear to no avail as we have had this little exersize closed down by god herself who caught one of the lads and followed him back here.
I can however keep the computer with it all installed so wait till I get home again.
Looks like I am on the move again so shutting down and crating it up for play at a later date.
one of the lads procured 3 tractors x,y,z. I think he got the wrong idea look for motors.
 

Jimjam66

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Just out of interested what dose it cost to build a one

I followed the build guide on Build Your CNC, although not too closely be ause I had some ideas
Of my own. The electronics can be costly if you buy separate stepper motor controllers rather than a breakout board with integrated controllers, but that's the route I went for ease of future expansion.

Steppers are cheaper than servos and I haven't had problems with mine. I guess overall the cost of my Mark I machine was about £350 including electronics. You could bring that down by about £120 by getting a breakout board with integrated stepper controllers. I didn't buy a mill for it as it used my router - worked okay but for Mark II I went with a 1.5kW mill and power inverter which add about £250 to the cost. Mark II also uses slide rails rather than skate bearings and angle iron, and proper lead screws rather than M10 threaded rod and studding connectors. Overall Mark II added about £600 to my original cost, for which I got much closer tolerances, far better control of RPM and significantly faster feedrate.
 

Jimjam66

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It might make sense to break down what you need:

A PC with a parallel port. (Nnewer is actually worse, only older boxes have parallel ports as standard. You don't need a whizz-bang processor or a vast HDD, so watch freecycle for someone giving away an old box.)

A Breakout Board (BOB). This connects to the parallel port on your PC and sends steps to the axial driver motors.

Three Stepper Motor Controllers (SMCs). These connect to the BOB and drive the axial motors. If you need to save money, you can get a BOB with three or four integrated SMCs on board for way cheaper than getting them separately.

Three stepper motors. Steppers are way cheaper than servos (and servo SMCs are more expensive than stepper SMCs). There are drawbacks (servos track their own state and feed back to the software so it can self-correct while steppers don't) but the cost difference more than outweighs these. Get steppers with sufficient holding power for what you want (mine are NEMA 23s with 340oz/inch holding power).

A 24 or 36 volt DC power supply, to power the SMCs (which in turn power the steppers).

Some means of having the gantry (X axis) 'slide' across the table and the Y axis 'slide' across the gantry and the Z axis 'slide' up and down on the Y axis. Build Your CNC shows a nifty way of using angle iron and skate bearings to do this, or you could adopt the pricier approach of using linear slide rails.

Some means of 'driving' the three axes mentioned above along their 'slideable range'. The cheap way is lengths of M10 threaded rod and captive studding nuts or the like, while a larger budget could opt for lead screws or toothed belts.

The actual machine can be made out of MDF or plywood (or welded steel if you're a metalworker). The cost of that is minimal, since you're likely to already have some or all of what you need. For wood framing, use furniture fixings like these and these.
 

Jimjam66

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David I might be teaching Grandma or I could earn Brownie points here.
I have been playing with EMC2 again and the boffins have shown me how to add g-code from inkscape by installing the plugin from here.
Extension repository - Inkscape Wiki
I hope it's a Brownie point situation:kiss::kiss:

George, I didn't even know that existed! Defo brownie points for you ... :frenchkiss:

I'll install and have a play! :thumbs:
 

clumsysod

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George, I didn't even know that existed! Defo brownie points for you ... :frenchkiss:

I'll install and have a play! :thumbs:

I might not be near a lathe or making pens at the moment but its nice to be able to contribute in another way.
There is so much more to this forum than just pens.
I wish you all success with it David, I can't do cnc either but I can run simulations and see how it would turn out and that is fascinating on its own.:winking::winking:
 

Jimjam66

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I might not be near a lathe or making pens at the moment but its nice to be able to contribute in another way.
There is so much more to this forum than just pens.
I wish you all success with it David, I can't do cnc either but I can run simulations and see how it would turn out and that is fascinating on its own.:winking::winking:

If you come up withsomething and want to see how it would look in the flesh (in the wood?) email it to me and I'll run it for you.
 

clumsysod

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God should know better than telling me I cant do something.
A 4 axis parallel controller board hitched a lift thanks to logistics to my very fleapit.
Over the last few days the lads have been to IT scrap yard and saved some stepper motors from Plotters or printers or some such wizardry.
A redundant filing cabinet supplied the runners and a bit of Dexion for a gantry.
A lot of assistance from the boffins to assemble and do the maths and wiring diags.
I supplied the dremel and bits and the vast experience I have gained whilst playing with EMC2 to produce my first cnc engraving.
Absolutely appalling result but the lads celebrated a huge success and much merriment is partaking.
Mark 2 will have cam belts driving it, threaded stud has too much play in it.
A long way to go yet but all participants have an object with their name poorly engraved in or on it.
Eat your heart out Heath Robinson Here is the first attempt at cnc engraving from the George mark 1 on a piece of chrome tube, the camera couldn't do it justice.
1.JPG
2.JPG
 

Jimjam66

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Fan-bloody-tastic, mate! You are a force of nature ...

Chrome was interesting choice of material to engrave, something softer might not have deflected so much? Either way, colour me impressed!
 

clumsysod

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Fan-bloody-tastic, mate! You are a force of nature ...

Chrome was interesting choice of material to engrave, something softer might not have deflected so much? Either way, colour me impressed!
We did discover that a chrome tube was a tad daring as the first object, a knife blade was next which came out better. then with a new bit a diamond tipped pointy thing did a brass zippo to a reasonable standard.
We are getting there.

Alex Yes it could do pen clips with the right configuration and something to hold a small item to the table 2mm font height is the smallest I have done so far.
David is still the man to see, his work is far superior to what I could produce with this setup, I am just playing to pass the time between excersize.
Watch this space though I haven't finished yet :rolling:
 
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