I've decided to ignore the recommendations of my psychiatric counselor and go ahead and design and build a benchtop CNC router; afger all, woodworking and time in the workshop is the best therapy there is.
The target dimensions for this are 36" x 18" x 6" of motion. I've got a headstart on it. I've been lurking here for a few weeks and have been reading everything I can find on the subject. I've got about as many questions at this point as I've got answers (unfortunately, none of the answers I've got go with any of the questions). That's where you all come in. If you are willing to offer up your VAST knowledge, I'd be more than greateful to take whatever you can give. In exchange, I'll be glad to post pictures of the progress I'm making along the way, tell you what I've done that worked, and even show off the stuff I do that doesn't. Hopefully, with your help, I won't make too many mistakes, because my budget is tight.
I'm a mechanical engineer, so I have first hand experience in what doesn't work, and I've tinkered with things mechanical and electrical for the majority of my life. I'm good with my hands and still have all of my fingers (bonus, they all still work too). I love woodworking and have done some metalworking too (mostly aluminum). Together, I hope we can point me in the right direction and leave a trail of information for DIYers to come. I stand here on the shoulders of those who came before me and hopefully someone will stand on my shoulders in the future. Enough with the introductions, let's get to designing a CNC router....
Here's what I have so far:
I've got some samples from PBC linear, two redi rail carriers that I plan to use for the Y axis, a Dolphin assembly carrier and 9.5" of 75mm wide track that I'll use for the Z axis. These are nice carriers with very tight specifications; all in, about $300 worth of samples.
I've got 3 NEMA 23 about 300 oz-in steppers and controllers that should be suitable for all 3 axes and a computer that I'll get linuxCNC going on.
I've got some 3/4" plywood as well as some 1/2" acrylic.
Most importantly, I've got an air conditioned workshop with a fair amount of power tools (drill press, table saw, jointer, soldering iron, etc) and a bunch of free time waiting to be utilized with a really cool project.
I've also got a working copy of autocad and I've been doing some drawings. I'll post them for everyone to see and critique.
Here are my thoughts and some questions....
I'd like to use the acrylic for the gantry. It's fairly rigid and easily machined. It is also dimensionally stable . Your thoughts on that would be great.
I believe I should use acme or ball screws for the lead screws. Acme screws are within my budget but i'm not sure if I should use 1 of 5 start screws or a combination of the 2. A single 6' screw will be sufficient for the project, but if a combination of 1 and 5 start makes sense, I'll find budget for that.
I need to purchase some redi rail for the Y axis and even though it is slightly more expensive that just some fully supported rail and bearings, I think the slight additional cost will be worth it.
I plan to use Linear carriages from CNCrouterparts.com and cold rolled 1/4" x 2" bar for the x axis. Not sure what to use for the bed, but thinking either acrylic or 3/16" steel plate with a sacrificial wood sheet over it.
I'll also need to purchase bearings, bolts, lead screw supports, and I'm sure more stuff that I haven't thouht of yet.
That should be enouhg for my first post. I patiently await your input. Thanks in advance for whatever input you can provide. Hopefully, together we can make me a seriously kick-ass new tool and leave a trail that is easily followed by other new to the hobby DIYers.
The target dimensions for this are 36" x 18" x 6" of motion. I've got a headstart on it. I've been lurking here for a few weeks and have been reading everything I can find on the subject. I've got about as many questions at this point as I've got answers (unfortunately, none of the answers I've got go with any of the questions). That's where you all come in. If you are willing to offer up your VAST knowledge, I'd be more than greateful to take whatever you can give. In exchange, I'll be glad to post pictures of the progress I'm making along the way, tell you what I've done that worked, and even show off the stuff I do that doesn't. Hopefully, with your help, I won't make too many mistakes, because my budget is tight.
I'm a mechanical engineer, so I have first hand experience in what doesn't work, and I've tinkered with things mechanical and electrical for the majority of my life. I'm good with my hands and still have all of my fingers (bonus, they all still work too). I love woodworking and have done some metalworking too (mostly aluminum). Together, I hope we can point me in the right direction and leave a trail of information for DIYers to come. I stand here on the shoulders of those who came before me and hopefully someone will stand on my shoulders in the future. Enough with the introductions, let's get to designing a CNC router....
Here's what I have so far:
I've got some samples from PBC linear, two redi rail carriers that I plan to use for the Y axis, a Dolphin assembly carrier and 9.5" of 75mm wide track that I'll use for the Z axis. These are nice carriers with very tight specifications; all in, about $300 worth of samples.
I've got 3 NEMA 23 about 300 oz-in steppers and controllers that should be suitable for all 3 axes and a computer that I'll get linuxCNC going on.
I've got some 3/4" plywood as well as some 1/2" acrylic.
Most importantly, I've got an air conditioned workshop with a fair amount of power tools (drill press, table saw, jointer, soldering iron, etc) and a bunch of free time waiting to be utilized with a really cool project.
I've also got a working copy of autocad and I've been doing some drawings. I'll post them for everyone to see and critique.
Here are my thoughts and some questions....
I'd like to use the acrylic for the gantry. It's fairly rigid and easily machined. It is also dimensionally stable . Your thoughts on that would be great.
I believe I should use acme or ball screws for the lead screws. Acme screws are within my budget but i'm not sure if I should use 1 of 5 start screws or a combination of the 2. A single 6' screw will be sufficient for the project, but if a combination of 1 and 5 start makes sense, I'll find budget for that.
I need to purchase some redi rail for the Y axis and even though it is slightly more expensive that just some fully supported rail and bearings, I think the slight additional cost will be worth it.
I plan to use Linear carriages from CNCrouterparts.com and cold rolled 1/4" x 2" bar for the x axis. Not sure what to use for the bed, but thinking either acrylic or 3/16" steel plate with a sacrificial wood sheet over it.
I'll also need to purchase bearings, bolts, lead screw supports, and I'm sure more stuff that I haven't thouht of yet.
That should be enouhg for my first post. I patiently await your input. Thanks in advance for whatever input you can provide. Hopefully, together we can make me a seriously kick-ass new tool and leave a trail that is easily followed by other new to the hobby DIYers.