another chris, the Introduction
December 3, 2009 at 2:49 pm #2238
Congratulations on the site and plans, nice work.
I already have a cnc machine, it is a combination mill and turning rig. Together with a friend we converted a conventional machine ( a picture of it can be found here: http://www.flickr.com/photos/jiskar/3969174253/)
We use linux with emc, works like a charm and it’s free. But a paid solution like Mach3 can have it’s advantages.
Well our machine is mainly for aluminum and steel, we have low-rpm spindles and relative low feed-speeds. Due to my interest towards parametric design and digital fabrication techniques, I want to build another machine, this time optimized for foam cutting and other light stuff. So your plans look very promising. Especially the simple methods and cheap method used to make the guidance system.
I do have a few questions.
What kind of slack do you encounter in the system?
How well do your x and y axis threading work?
What is you resolution?
What is your maximal free run speed (no cutting just moving the gantry around)?
sorry for all the questions.
cheers chrisDecember 3, 2009 at 10:04 pm #3273
We completed the DIYLILCNC just in time for a show in Chicago. Due to the time crunch, we installed the device before we had the opportunity for rigorous testing.
When the show comes down in January, we’ll post more info on what the design can do. In the meantime:
Threading: X/Y are run on a pulley and belt system. This seems to work pretty well, even though we are casually setting belt tension by feel. Slipping, when it does occur, seems to happen within the motor (as opposed to the belt slipping on the pulley).
Slack: Here I’m assuming you mean inconsistencies in the movement of the gantry. When cutting harder materials and/or running the motors too fast, the steppers can sometimes lose position. EMC programming can solve the speed issue by limiting speed/acceleration, but we’ll need more time to figure all the materials that cause problems.
There’s no such thing as too many questions!December 3, 2009 at 10:17 pm #3274
Hey Chris, thanks for introducing yourself. Looks like you guys have a nice setup–I like your chaotic shelves as well!
As to your questions:
>What kind of slack do you encounter in the system?
I’m not exactly sure what you mean by slack, could you elaborate?
>How well do your x and y axis threading work?
The X and Y axes are actually belt-driven, and they work pretty well. There’s a motor on the back of the Z-cart that moves the tool in X, and one on the side that rotates a shaft that extends through the entire gantry to drive both vertical sides evenly in Y. We talk a little about how the Y drive could be improved in the conclusions section of the instructional PDF (in the downloads section)
>What is your resolution?
At the coarsest resolution (X and Y axes) we get about 0.004″/step. The Z is much higher, around 0.0003″/step. We haven’t figured out a reliable way to test the precision of the actual cuts yet, that is how much a milled piece deviates from the original CAD model.
>What is your maximal free run speed (no cutting just moving the gantry around)?
The highest I’ve tried is 300 inches per minute in the X and Y axes, and about 42 inches per minute in the Z. It could maybe go a little faster, but with a small gantry like ours it runs out of room quickly.July 28, 2011 at 12:07 pm #3275
It is along time ago, that I was here. In the meantime I opend a lasercutting shop in the Netherlands. I saw the diylilcnc v2 on kickstarter, good idea!
I want to cut out a set of the latest v1 model. I nested it in 3 sheets of 122 by 60 cm 6mm MDF board. ( that is the workdimension of our machine) I will make some test regarding the imperial en metric diverences. Good luck and thank you again for the plans. ( and the rhino model )August 3, 2011 at 11:04 pm #3276
Great! We always love to hear about projects in a new country. Please send pictures!
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