Here is my first attempt at creating software that can create G-Code to control Cal's homemade CNC machine. Right now all my arcs are radial but I will be adding more capability in the future.
http://www.skibuilders.com/cpg/displayi ... at=0&pos=0[/url]
WheezerWare
Moderators: Head Monkey, kelvin, bigKam, skidesmond, chrismp
WheezerWare
Last edited by Wheezer on Mon Jan 07, 2008 9:54 am, edited 1 time in total.
That's some serious stuff you've got going there. We've seen specialized CAD software for ski builders, but I haven't seen specialized CAM software before now. It looks like you're putting together a CAD/CAM combination... correct? I'll certainly be watching with great interest for future developments.
G-man
G-man
G-man: I remember that you we starting down the CNC path last spring and I had hoped you would have beaten me to this point cause I have no knowledge in the CAD/CAM realm. My son Cal (*Armada*) built a 8 foot CNC router for his high school senior project. It languished (95% complete) on the dining room table from June till Xmas when my wife finally forced us to move it to the shed. I have been experimenting with profiling of my cores with it with some success. We tried cutting out some bases with NO success. We have high hopes for the machine but for now I'm going to be using it for profiling and cutting out templates.
We are using MACH3 (artsoft.com) as the stepper motor controller. This uses G Code as the control language. MACH3 has a tool (LazyCam) which converts .dxf files to G Code but MACH3 (the free version) has a limit to the number of lines of code. I have been unsuccessful in my attempts to take a design in SNOCAD and get it into MACH3 so I decided to write my own software. (Everyone on the forum understands the compulsion to make your own shit.)
I have a lot more features to add to my program but when it is a little more robust I will be happy to share it with you. (Executable or source code.)
We are using MACH3 (artsoft.com) as the stepper motor controller. This uses G Code as the control language. MACH3 has a tool (LazyCam) which converts .dxf files to G Code but MACH3 (the free version) has a limit to the number of lines of code. I have been unsuccessful in my attempts to take a design in SNOCAD and get it into MACH3 so I decided to write my own software. (Everyone on the forum understands the compulsion to make your own shit.)
I have a lot more features to add to my program but when it is a little more robust I will be happy to share it with you. (Executable or source code.)
Hey Wheezer,
Your last post kinda cracked me up. Guess where my nearly finished CNC machine is sitting right at this moment... on the kitchen table!! The Z and Y axis are operational and I'm playing around with Mach 3, getting everything tuned up. I've tried to import and run some g-code, but my old 233MHz PC with 64M of RAM is just not up to the task (most of my computers are Mac's). So, I'm lookin' for a new mainboard and cpu to get the old case up to speed. The old PC computer jogs the Z and Y axis just fine, so I'll use it for the next 3 weeks, or so, until I'm ready to do some serious work with the machine. My x axis (main cutting table) is equipped as a vacuum table. I've been using vacuum clamping for quite awhile for cutting out my base material (with a pin-router and template up until now) an it works really well. It takes about one minute to cut out a base with the vacuum set-up. I also use a vacuum table on my profiler. I plan to use vacuum for pretty much everything on the CNC machine. What problems did you encounter with cutting out your bases? I know that the free version of Mach 3 is limited to 500 lines of G-code. How many lines of code are you generating when you convert your ski core CAD drawings to G-code? I've read on some of the CNC forums that LazyCam is quite limited in the Mach3 free version. I'm going to buy the full version, so maybe I can find out if the full-package LazyCam will import from SNOCAD any easier than it will in the free version. I'm quite impressed that you are writing your own software... but yes, I do understand the 'compulsion'... unlike my usually understanding and wonderful wife (she's given me one more month of residence on the kitchen table be before me and the machine are banished to the dreaded shed).
kelvin, did you guys build your own CNC? Let's see a pic or two. As I get the hang of the software, maybe I can chime in with something worthwhile now-and-again. Fun times ahead.
G-man
Your last post kinda cracked me up. Guess where my nearly finished CNC machine is sitting right at this moment... on the kitchen table!! The Z and Y axis are operational and I'm playing around with Mach 3, getting everything tuned up. I've tried to import and run some g-code, but my old 233MHz PC with 64M of RAM is just not up to the task (most of my computers are Mac's). So, I'm lookin' for a new mainboard and cpu to get the old case up to speed. The old PC computer jogs the Z and Y axis just fine, so I'll use it for the next 3 weeks, or so, until I'm ready to do some serious work with the machine. My x axis (main cutting table) is equipped as a vacuum table. I've been using vacuum clamping for quite awhile for cutting out my base material (with a pin-router and template up until now) an it works really well. It takes about one minute to cut out a base with the vacuum set-up. I also use a vacuum table on my profiler. I plan to use vacuum for pretty much everything on the CNC machine. What problems did you encounter with cutting out your bases? I know that the free version of Mach 3 is limited to 500 lines of G-code. How many lines of code are you generating when you convert your ski core CAD drawings to G-code? I've read on some of the CNC forums that LazyCam is quite limited in the Mach3 free version. I'm going to buy the full version, so maybe I can find out if the full-package LazyCam will import from SNOCAD any easier than it will in the free version. I'm quite impressed that you are writing your own software... but yes, I do understand the 'compulsion'... unlike my usually understanding and wonderful wife (she's given me one more month of residence on the kitchen table be before me and the machine are banished to the dreaded shed).
kelvin, did you guys build your own CNC? Let's see a pic or two. As I get the hang of the software, maybe I can chime in with something worthwhile now-and-again. Fun times ahead.
G-man
G-Man,
We tried to hold the base down with weights which we moved to keep them away from the router path but the Ptex wouldn't lie flat. It would curl up when cut resulting in scalloping along the edge. For now I would be happy with making a template and using my hand router.
So I tried last night to make a template out of an old piece of poplar. Filled the shed with smoke and I had to quit. I think part of the problem was the groove filled up with sawdust and got too compacted. I have ordered some different style bits that hopefully will help. I'm also going to put shims under the board and fully penetrate it.
So how does your vacuum setup work? do you have some sacrificial material like pegboard under the core?
We tried to hold the base down with weights which we moved to keep them away from the router path but the Ptex wouldn't lie flat. It would curl up when cut resulting in scalloping along the edge. For now I would be happy with making a template and using my hand router.
So I tried last night to make a template out of an old piece of poplar. Filled the shed with smoke and I had to quit. I think part of the problem was the groove filled up with sawdust and got too compacted. I have ordered some different style bits that hopefully will help. I'm also going to put shims under the board and fully penetrate it.
So how does your vacuum setup work? do you have some sacrificial material like pegboard under the core?
Wheezer,
I cut out my first bases tonight with our cnc. I had the same curling problem, since I don't yet have vacuum hold downs. What I did was use turner's tape (http://www.rockler.com/product.cfm?page ... ers%20tape) to hold the base down and used a 1/4" spiral downcut router bit. The downcut bit helps to push the material down as it cuts.
For cutting your templates and anything thicker, you probably want to use a spiral upcut bit. This bit will eject the waste material much better.
I'm still learning as I go.
-kelvin
I cut out my first bases tonight with our cnc. I had the same curling problem, since I don't yet have vacuum hold downs. What I did was use turner's tape (http://www.rockler.com/product.cfm?page ... ers%20tape) to hold the base down and used a 1/4" spiral downcut router bit. The downcut bit helps to push the material down as it cuts.
For cutting your templates and anything thicker, you probably want to use a spiral upcut bit. This bit will eject the waste material much better.
I'm still learning as I go.
-kelvin
Hey Wheezer,
Somehow I missed your last post until this morning.
Vacuum clamping when used on a pin router is 'backwards' from how it is done with a CNC machine. For the pin router, I just make a template that is exactly the size/shape that I want the production parts to be. Then, I route a 3/8 wide x 1/16 deep groove in the face of the template (the groove runs around the perimeter of the template, about 1/4 inch back from the outer edge) that I place some 1/8 thick sticky-backed foam tape in. The tape provides for a vacuum seal between the template and the part to be cut. The vacuum hose fitting is mounted in the opposite side of the template. I use my compressor/vacuum generator (foot pedal operated) for this process. After the vacuum template is holding the base material, I just run it around the pin router for a perfectly cut out base... takes maybe 20 seconds... then, step on the pedal to release the part... then, lay the template on the next piece and step on the pedal and cut the next piece. The pin router method is great for production when I want to make a lot of parts that are the same size.
For one-off parts though, the CNC is the way to go. As kelvin indicated, the spiral up-cut bit (about 1/4 diameter) is a great way to go on a CNC machine because the up-cut bit clears the chips and allows the dust collection system to take them away. But as you have suggested, holding down the part can be a problem when the up-cut bit is wanting to lift the part. So, vacuum hold-down is really the best way to go. I'm just finishing up my X-axis vacuum table and I'll be posting pictures after I get it tested and painted. Basically, it is a big ol' torsion box (ribs with an outer skin). The box is air tight except for a 'tunnel' down the longitudinal center of the box. For this vacuum system, I'll use a shop vac, which I have been using with my profiler with very good results. So the shop vac connects to one end of the 'tunnel' and there is an adjustable vent gate at the other end of the tunnel. The vent gate will allow for adjustment of vacuum pressure so that the shop vac doesn't overheat. The main top surface of the cutting table is smooth with a couple of holes that exit from the vacuum tunnel. At each end of the table is a 1/2 inch index/locater pin that extends up from the table about 2 inches. The vacuum clamping layer will slip over these pins. The vacuum layer consists of a 7"x 80" piece of 1/2 in MDF that has a foam tape perimeter on the bottom (for sealing to the table) and a foam tape perimeter (for holding down the UHMW base material) on the top. The clamping layer has a series of through holes to allow vacuum pressure to be effective at both sides of the layer. So, the process goes like this... the vacuum layer gets placed over the index pins, then the base 'blank' gets placed on top of the vacuum layer (which also functions to some degree as a sacrificial surface). The base blank also has holes in it that slip over the index pins... this way the vacuum pressure does not have to hold the base material in proper location, it just has to hold the base material down. Then, the vacuum is turned on and the cutting begins. I'll probably have to temporarily lay a piece of heavy MDF on the UHMW just long enough to press everything together to get the vacuum leaks sealed up. I've noticed that when the temperatures are cold, the foam tape is not as compliant and I have to work a bit (using a flat board as a weight) to get the vacuum leaks sealed up. Also, I try to get the foam tape seal as close to the actual cutting edge as possible so that I have a lot of holding pressure where the bit is trying the lift the material. Foam sealing tapes come in all kinds of densities. Some are made specifically for vacuum clamping. I generally just use weather stripping foam tape. I find that it seals more easily on large surfaces. It doesn't work to well for preventing lateral shift of the workpiece (like the more specialized tapes do), but that's why I use the index pins.
I know it may be a bit difficult to understand all of my vacuum table explanation. I'll post pics when I get my table (and entire machine) painted and back together. The Kams set the bar pretty high with their nice paint jobs.
G-man
Somehow I missed your last post until this morning.
Vacuum clamping when used on a pin router is 'backwards' from how it is done with a CNC machine. For the pin router, I just make a template that is exactly the size/shape that I want the production parts to be. Then, I route a 3/8 wide x 1/16 deep groove in the face of the template (the groove runs around the perimeter of the template, about 1/4 inch back from the outer edge) that I place some 1/8 thick sticky-backed foam tape in. The tape provides for a vacuum seal between the template and the part to be cut. The vacuum hose fitting is mounted in the opposite side of the template. I use my compressor/vacuum generator (foot pedal operated) for this process. After the vacuum template is holding the base material, I just run it around the pin router for a perfectly cut out base... takes maybe 20 seconds... then, step on the pedal to release the part... then, lay the template on the next piece and step on the pedal and cut the next piece. The pin router method is great for production when I want to make a lot of parts that are the same size.
For one-off parts though, the CNC is the way to go. As kelvin indicated, the spiral up-cut bit (about 1/4 diameter) is a great way to go on a CNC machine because the up-cut bit clears the chips and allows the dust collection system to take them away. But as you have suggested, holding down the part can be a problem when the up-cut bit is wanting to lift the part. So, vacuum hold-down is really the best way to go. I'm just finishing up my X-axis vacuum table and I'll be posting pictures after I get it tested and painted. Basically, it is a big ol' torsion box (ribs with an outer skin). The box is air tight except for a 'tunnel' down the longitudinal center of the box. For this vacuum system, I'll use a shop vac, which I have been using with my profiler with very good results. So the shop vac connects to one end of the 'tunnel' and there is an adjustable vent gate at the other end of the tunnel. The vent gate will allow for adjustment of vacuum pressure so that the shop vac doesn't overheat. The main top surface of the cutting table is smooth with a couple of holes that exit from the vacuum tunnel. At each end of the table is a 1/2 inch index/locater pin that extends up from the table about 2 inches. The vacuum clamping layer will slip over these pins. The vacuum layer consists of a 7"x 80" piece of 1/2 in MDF that has a foam tape perimeter on the bottom (for sealing to the table) and a foam tape perimeter (for holding down the UHMW base material) on the top. The clamping layer has a series of through holes to allow vacuum pressure to be effective at both sides of the layer. So, the process goes like this... the vacuum layer gets placed over the index pins, then the base 'blank' gets placed on top of the vacuum layer (which also functions to some degree as a sacrificial surface). The base blank also has holes in it that slip over the index pins... this way the vacuum pressure does not have to hold the base material in proper location, it just has to hold the base material down. Then, the vacuum is turned on and the cutting begins. I'll probably have to temporarily lay a piece of heavy MDF on the UHMW just long enough to press everything together to get the vacuum leaks sealed up. I've noticed that when the temperatures are cold, the foam tape is not as compliant and I have to work a bit (using a flat board as a weight) to get the vacuum leaks sealed up. Also, I try to get the foam tape seal as close to the actual cutting edge as possible so that I have a lot of holding pressure where the bit is trying the lift the material. Foam sealing tapes come in all kinds of densities. Some are made specifically for vacuum clamping. I generally just use weather stripping foam tape. I find that it seals more easily on large surfaces. It doesn't work to well for preventing lateral shift of the workpiece (like the more specialized tapes do), but that's why I use the index pins.
I know it may be a bit difficult to understand all of my vacuum table explanation. I'll post pics when I get my table (and entire machine) painted and back together. The Kams set the bar pretty high with their nice paint jobs.
G-man