Ok, who's going to be the first one to get this little CNC baby
02-16-2008, 07:24 PM
#1
Rennlist Member
Thread Starter
Ok, who's going to be the first one to get this little CNC baby
http://www.craftsman.com/carve/index...20080129x00006
Interesting. I wonder how fast the prices will drip AND people will modify it for use with metal work. That'd be pretty neat.
Of course there's this place that might be interesting:
http://www.emachineshop.com/
Interesting. I wonder how fast the prices will drip AND people will modify it for use with metal work. That'd be pretty neat.
Of course there's this place that might be interesting:
http://www.emachineshop.com/
02-16-2008, 07:56 PM
#3
Nordschleife Master
that emachine shop thing is really cool, i would love to play with that, hell what would i design first?
I need a new mac that i can run Windows on, crap!
I need a new mac that i can run Windows on, crap!
02-16-2008, 09:08 PM
#5
Rennlist Member
I'm tired of making blueprints & farming out work to my brother, I'm getting one of these...
http://www.lathemaster.com/HEAVYDUTY...E%207045FG.htm
I did some research & quite a few guys on a BMW list are using it & gave it great reviews.
Hammer
http://www.lathemaster.com/HEAVYDUTY...E%207045FG.htm
I did some research & quite a few guys on a BMW list are using it & gave it great reviews.
Hammer
02-17-2008, 12:00 AM
#6
Rennlist Member
For about the same price you can get in the a system that is capable of metal and plastics. Desktop cnc mills are available at www.sherline.com or www.taigtools.com. Personally I use a sherline based system with the X and Y axis upgraded with parts from a2z cnc, and various other upgrades. You alos need software to make the TAP files and software to run the mill. I use bobcad and turbocnc. The big limitations are these:
1) Having a mill or lathe does not make you a machinist. There is lots to learn.
2) If you want to do metal you will need a space where you don't mind having a lot of metal chips around. They will end up friggen everywhere. And you really dont want those little wonders tracked into the house where they can be stepped on with bare feet.
3) You will want a space where you don't mind a lot of noise and the smell of the cutting fluid. If you want to cut metal dry you will have to go very slowly.
4) The small machines (like sherline and Taig) work great on plastics, and OK on aluminum but they are not really as rigid as you would like for anything harder. Even the aluminum is pushing it. The next step is a conversion based on something like HF's Mill-Drill, but you are looking at something like 700lbs so you had better some way to move it around and a slab to put it on.
1) Having a mill or lathe does not make you a machinist. There is lots to learn.
2) If you want to do metal you will need a space where you don't mind having a lot of metal chips around. They will end up friggen everywhere. And you really dont want those little wonders tracked into the house where they can be stepped on with bare feet.
3) You will want a space where you don't mind a lot of noise and the smell of the cutting fluid. If you want to cut metal dry you will have to go very slowly.
4) The small machines (like sherline and Taig) work great on plastics, and OK on aluminum but they are not really as rigid as you would like for anything harder. Even the aluminum is pushing it. The next step is a conversion based on something like HF's Mill-Drill, but you are looking at something like 700lbs so you had better some way to move it around and a slab to put it on.
02-17-2008, 12:24 PM
#7
Three Wheelin'
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The big limitations are these:
1) Having a mill or lathe does not make you a machinist. There is lots to learn.
2) If you want to do metal you will need a space where you don't mind having a lot of metal chips around. They will end up friggen everywhere. And you really dont want those little wonders tracked into the house where they can be stepped on with bare feet.
3) You will want a space where you don't mind a lot of noise and the smell of the cutting fluid. If you want to cut metal dry you will have to go very slowly.
4) The small machines (like sherline and Taig) work great on plastics, and OK on aluminum but they are not really as rigid as you would like for anything harder. Even the aluminum is pushing it. The next step is a conversion based on something like HF's Mill-Drill, but you are looking at something like 700lbs so you had better some way to move it around and a slab to put it on.
1) Having a mill or lathe does not make you a machinist. There is lots to learn.
2) If you want to do metal you will need a space where you don't mind having a lot of metal chips around. They will end up friggen everywhere. And you really dont want those little wonders tracked into the house where they can be stepped on with bare feet.
3) You will want a space where you don't mind a lot of noise and the smell of the cutting fluid. If you want to cut metal dry you will have to go very slowly.
4) The small machines (like sherline and Taig) work great on plastics, and OK on aluminum but they are not really as rigid as you would like for anything harder. Even the aluminum is pushing it. The next step is a conversion based on something like HF's Mill-Drill, but you are looking at something like 700lbs so you had better some way to move it around and a slab to put it on.
+1,+2,+2,+4.
Excellent post, Karl.
I would only get a "desktop" machining center for little things, like RC car parts. I would outsource anything heavier than that to a shop.
Note that the unit Fraggle posted a link to is targeted to woodworking and mentions plastics and foam as possible. NO metal.
IMO, for real car parts real CNC equipment is required, which needs a real shop environment to function safely and a real machinist to function correctly. IMO, IMO, IMO.
- Josh
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02-17-2008, 12:45 PM
#8
Rennlist Member
I mostly agree Josh. Except that I do make lots of parts for my cars on my desktop machines. But the key is that I primarily use the machines for my business, and just for the cars as an afterthought. I think it would be hard to justify the cost of the machines and the time it takes to get them working right and learn how to use them just for a car hobby. Particularly given the sometimes-not-so-great results and the amount of time it takes to try makeing a part 5 or 6 times when you don't really know what you are doing. After doing this for 4 or 5 years I have pretty good desktop setups and am reasonably experienced (although still totatally uneducated) and I am very comfortable using my mill to make things like brackets to move the rear seat backs forward in my convertable and parts for the top latches. But I am going to need a supercharger pully pretty soon an that is going to go to emachineshop.com.
For my business we use the mills to make plastic parts (mostly HDPE and PC) and I find that these are often a great way to bridge the gap between FDM or SLA prototype parts and molded parts. These days you can get molded parts quickly (if you are willing to pay more), but I find that I often don't want to commit a design to a mold until I have build and shipped 50 or 100 devices that use them and have really worked out all the little issues.
For my business we use the mills to make plastic parts (mostly HDPE and PC) and I find that these are often a great way to bridge the gap between FDM or SLA prototype parts and molded parts. These days you can get molded parts quickly (if you are willing to pay more), but I find that I often don't want to commit a design to a mold until I have build and shipped 50 or 100 devices that use them and have really worked out all the little issues.
02-17-2008, 01:33 PM
#9
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For my business we use the mills to make plastic parts (mostly HDPE and PC) and I find that these are often a great way to bridge the gap between FDM or SLA prototype parts and molded parts. These days you can get molded parts quickly (if you are willing to pay more), but I find that I often don't want to commit a design to a mold until I have build and shipped 50 or 100 devices that use them and have really worked out all the little issues.
That got my interest - one problem we have at my work is bridging that same gap: the FDM takes 40+ hours to produce a peice that looks like the part but has far different material properties and the design first has to be finished to perfection in CAD (a stretched resource!). Prototype molding (injection) is $$$$$ Money and Time x 10. Meanwhile, there's a real need to test-and-tune proposals in real-life fitment, but we have very limited access to proper machining equipment - it all belongs to a neighboring "little kingdom" in our company that's stingy with sharing their resources.
I'm going to dwelve into the desktops centers a little more deeply... thanks for the ideas Karl.
02-18-2008, 03:10 AM
#10
Rennlist Member
That's it exactly. The material quality of both FDM and SLA is just not good enough to ship in a product. Plus it is too expensive. Plus the Z axis accuracy of FDM is crap. Unfortunatly, you cannot buy a desktop CNC mill that is very good (at least I have not found one for a reasonable price). But you can buy all the parts from four or 5 different vendors and assemble a pretty darn good system yourself for under 1.5K. Plus design software, of course. Email or P.M. me if you want detail on this. I am on my 5th generation of system and have tried a few things.
02-18-2008, 09:50 PM
#11
Rennlist Member
Thread Starter
Interesting learning here! I am into nitro RC cars as well as my porsches, and sometimes tire of working parts on my single axis machine (drill press!)
I do agree with Ryan, the cost is a little high, especially when it is focused on wood - no metal options.
and true to all, nothing beats a true machinist and a full shop.
I do agree with Ryan, the cost is a little high, especially when it is focused on wood - no metal options.
and true to all, nothing beats a true machinist and a full shop.
02-21-2008, 03:50 AM
#12
Rennlist Member
This may be more than anybody want to know right off, but I though I would put it together and post it here. Sort of as a reference.
I have build and re-built a whole bunch of systems, mostly Sherline based. There are three main companies that build desktop mills: MaxNC, Sherline, and Taig. MaxNC stuff is crummy and the support is worse, Taig looks pretty good, but kinda cabbaged together, and I worry about support, and Sherline stuff is small, but the support is top notch. Support is important as you will break and wear stuff out all the time and you will need parts. With Sherline you can get any part next day for a fair price. And Sherline has the most third party support in terms of tools and clamps and such.
The biggest problems with a small mill is 1) they are too small, and 2) they are not really set up for CNC. Even after you have adapted them. 1) With a standard Sherline mill you get something like 4" of Y axis travel and 7" of X travel. It sounds like a lot but after you have the material clamping in place and have taken everything into account you are looking at making parts with a maximum size of something like 2.5" by 5". Just not enough. So you are gonna want a bigger table. 2) All of these mills come with 20tpi lead screws. This is great for hand milling because one turn is 0.050, and that gives you a real ability to get good enough resolution by hand. But for CNC this is a big problem because once you get the speed up to a reasonable number (say 10ipm) the motors are turning so fast that they are generating tons of back EMF and all your drive voltage is going into fighting that rather than generating torque by putting current throught the motor.
The best solution I have build it this:
It starts with a Z axiz from Sherline. Just the vertical column, spindle and spindle motor. Also, I use their axis motor mounts, hand wheels, gibs and other misc parts. www.sherline.com.
The X and Y tables and lead screws are from a2zcnc. Their table are fully compatible with sherline stuff but much bigger and beefier. Also, their lead screw system if 5tpi, which is much more optimal for CNC. And it has backlash really well managed. Sherline has a hokey system for managing backlash, and MaxNC pretty much none at all. If you want to cut round patterns and have them come out round your backlash has to be really well under control. www.a2zcnc.com
A quite reasonable motor control system is made by xylotex. Prices are good, the controllers are fast and flexible, and support is pretty good. They have a three axis package with the power supply, the stepper motor contoller board, fan, and stepper motors. I get my stepper motors somewhere else (I prefer Pacific Scientific motors). But their complete package (3 axis system kit) is one stop shopping with all good stuff for a good price. www.xylotex.com
If have to use different tools to make a part you will be changing them a lot and it gets to be a pain. I like the rapid changer from High Tech Systems LLC. www.hightechsystemsllc.com
You can start out with cutters from McMaster or anywhere else. But if you start to get serious about a particular material you will get MUCH better performance with a cutter designed for the specific material. I use cutters from Onsrud, and have had really great luck with them, and they will help you find the optimal cutter and feed rates for your specific material. www.plasticrouting.com
CNC process are controlled in a language called 'G code'. It looks a lot like a gerber file, if you know what that is. You will need something to read the G code file and run the motors of the mill. Find a used $50 laptop with a good parallel port (interfaces to the mill) and a good floppy (for bringing in the files), that can boot and run MSDOS. Then download TurboCNC for FREE! It works really well and for $20 you can even get the source and modify it (but you won't need to). www.dakeng.com
You will also need something to create the G code files. You can do it by hand, I suppose, if you are just doing straight lines, but circular patters are tricky. There are also programs that take 3D files and can completely generate programs to do a complete contour of the parts. Such as add-ins to SolidWorks. The problem with these it that they often take forever to cut, because they are not smart about taking advantage to specific geometry of the part and the material. I use a older version of a program called BobCad. With this program I can work in something called 2 1/2 D and can quickly generate files in a sort of semi-automatic way that run quickly on the mill. I think they may have priced them selves out of the market. When I bought my program it was under $500, and I think it was sort of similar to what they currently call their HobbyPro (oxymoron alert!). Their price on the new program is too high, but it you are interested you might want to call them. As I recall they sold me my package for way way under the advertised price. If you folks are already using a CAD system you might want to see what is available as an add on. But don't try to use anything too automated or 3D oriented or it will take forever to cut.
One of the big challenges is fastening the material to the mill. You are forever trying to figure this out and adapting for each job. I finally simplified this by setting up my mills to take a fixed size material+underlayment (in my case 4"x10"x1") with toggle clamps on either side of the x axis to fasten down a block this size. This way I almost never have to fuss with the fastening, I just cut my material this size, pick an underlayment to make the thickness come out right, clamp it down and go. Saves a lot of time and trouble. Wastes a bit of material though. You would not want to do this if you were cutting a lot of Delrin or something that is expensive, but with something like HDPE it is not a problem.
All this sounds like a lot but remember that the only 'building' you have to do here is screwing things together, wiring them up, and setting up the software. The mill and such will cost you something like $1.5 K, and the cad software can cost you anywhere from nothing to much more than the mill.
I have build and re-built a whole bunch of systems, mostly Sherline based. There are three main companies that build desktop mills: MaxNC, Sherline, and Taig. MaxNC stuff is crummy and the support is worse, Taig looks pretty good, but kinda cabbaged together, and I worry about support, and Sherline stuff is small, but the support is top notch. Support is important as you will break and wear stuff out all the time and you will need parts. With Sherline you can get any part next day for a fair price. And Sherline has the most third party support in terms of tools and clamps and such.
The biggest problems with a small mill is 1) they are too small, and 2) they are not really set up for CNC. Even after you have adapted them. 1) With a standard Sherline mill you get something like 4" of Y axis travel and 7" of X travel. It sounds like a lot but after you have the material clamping in place and have taken everything into account you are looking at making parts with a maximum size of something like 2.5" by 5". Just not enough. So you are gonna want a bigger table. 2) All of these mills come with 20tpi lead screws. This is great for hand milling because one turn is 0.050, and that gives you a real ability to get good enough resolution by hand. But for CNC this is a big problem because once you get the speed up to a reasonable number (say 10ipm) the motors are turning so fast that they are generating tons of back EMF and all your drive voltage is going into fighting that rather than generating torque by putting current throught the motor.
The best solution I have build it this:
It starts with a Z axiz from Sherline. Just the vertical column, spindle and spindle motor. Also, I use their axis motor mounts, hand wheels, gibs and other misc parts. www.sherline.com.
The X and Y tables and lead screws are from a2zcnc. Their table are fully compatible with sherline stuff but much bigger and beefier. Also, their lead screw system if 5tpi, which is much more optimal for CNC. And it has backlash really well managed. Sherline has a hokey system for managing backlash, and MaxNC pretty much none at all. If you want to cut round patterns and have them come out round your backlash has to be really well under control. www.a2zcnc.com
A quite reasonable motor control system is made by xylotex. Prices are good, the controllers are fast and flexible, and support is pretty good. They have a three axis package with the power supply, the stepper motor contoller board, fan, and stepper motors. I get my stepper motors somewhere else (I prefer Pacific Scientific motors). But their complete package (3 axis system kit) is one stop shopping with all good stuff for a good price. www.xylotex.com
If have to use different tools to make a part you will be changing them a lot and it gets to be a pain. I like the rapid changer from High Tech Systems LLC. www.hightechsystemsllc.com
You can start out with cutters from McMaster or anywhere else. But if you start to get serious about a particular material you will get MUCH better performance with a cutter designed for the specific material. I use cutters from Onsrud, and have had really great luck with them, and they will help you find the optimal cutter and feed rates for your specific material. www.plasticrouting.com
CNC process are controlled in a language called 'G code'. It looks a lot like a gerber file, if you know what that is. You will need something to read the G code file and run the motors of the mill. Find a used $50 laptop with a good parallel port (interfaces to the mill) and a good floppy (for bringing in the files), that can boot and run MSDOS. Then download TurboCNC for FREE! It works really well and for $20 you can even get the source and modify it (but you won't need to). www.dakeng.com
You will also need something to create the G code files. You can do it by hand, I suppose, if you are just doing straight lines, but circular patters are tricky. There are also programs that take 3D files and can completely generate programs to do a complete contour of the parts. Such as add-ins to SolidWorks. The problem with these it that they often take forever to cut, because they are not smart about taking advantage to specific geometry of the part and the material. I use a older version of a program called BobCad. With this program I can work in something called 2 1/2 D and can quickly generate files in a sort of semi-automatic way that run quickly on the mill. I think they may have priced them selves out of the market. When I bought my program it was under $500, and I think it was sort of similar to what they currently call their HobbyPro (oxymoron alert!). Their price on the new program is too high, but it you are interested you might want to call them. As I recall they sold me my package for way way under the advertised price. If you folks are already using a CAD system you might want to see what is available as an add on. But don't try to use anything too automated or 3D oriented or it will take forever to cut.
One of the big challenges is fastening the material to the mill. You are forever trying to figure this out and adapting for each job. I finally simplified this by setting up my mills to take a fixed size material+underlayment (in my case 4"x10"x1") with toggle clamps on either side of the x axis to fasten down a block this size. This way I almost never have to fuss with the fastening, I just cut my material this size, pick an underlayment to make the thickness come out right, clamp it down and go. Saves a lot of time and trouble. Wastes a bit of material though. You would not want to do this if you were cutting a lot of Delrin or something that is expensive, but with something like HDPE it is not a problem.
All this sounds like a lot but remember that the only 'building' you have to do here is screwing things together, wiring them up, and setting up the software. The mill and such will cost you something like $1.5 K, and the cad software can cost you anywhere from nothing to much more than the mill.
02-21-2008, 04:12 AM
#13
Rennlist Member
6.0-
The mill you mentioned is one of many similar Chinese made mills. As I understand it the government in Tiawan set up a program the help manufacturers make these things. So now there are a lot of VERY similar ones from different Chinese makers. I have seen them at around $500. I think Harbor Freight's is under $1000. The quality and features vary a bit from vendor to vendor but they are all pretty similar. I was thinking of going this way, but decided that if I had the space and wanted to deal with something this heavy I would step on up to a used bridgeport. Ultra solid, ultra useful and totally proven. Used they can be had for the same price or even less. Sometimes much less. Of course the is a big difference between moving around something that is like 700lbs and moving around something that is like 2500lbs.
The mill you mentioned is one of many similar Chinese made mills. As I understand it the government in Tiawan set up a program the help manufacturers make these things. So now there are a lot of VERY similar ones from different Chinese makers. I have seen them at around $500. I think Harbor Freight's is under $1000. The quality and features vary a bit from vendor to vendor but they are all pretty similar. I was thinking of going this way, but decided that if I had the space and wanted to deal with something this heavy I would step on up to a used bridgeport. Ultra solid, ultra useful and totally proven. Used they can be had for the same price or even less. Sometimes much less. Of course the is a big difference between moving around something that is like 700lbs and moving around something that is like 2500lbs.
02-21-2008, 04:46 PM
#14
I use emachinshop, but I have yet to be able to figure out how to make pulleys, etc. Only simple shapes like belt covers, timing wheels, and bushings.
How would you make a ribbed pulley?
How would you make a ribbed pulley?
