building plasma table soon.need advice

[kermit582]

Hi I'm new to the site and I must say I have learned alot already. I will be building a 5x9 (4x8) cutting area table and I had a thought last night if I could use automobile power window motors to drive the table??? and if anyone has tried angle iron and bearing for rails if so how did it work?.
Thanks.

Travis

Hawthorne forge

[Torchhead]

Power window motors suffer from several things that would preclude them from consideration:

The are high current, high torque DC motors, intended for intermittent operation at 12VDC. Continuous operation would probable lead to overheating and failure. Most often they have a gearheads with lots of backlash (Bad). Finally you will need to provide positional feedback to the system for a DC motor of any kind so that calls for a full servo electronics backend and encoders on the motors or the moving mechanism.

Any DC motor can be made into a servo by adding positional feedback (encoders) BUT how good they will function as a servo is dependant on a lot of factors. Obviously servo motors are optimized for that type of operation.

My advice is to stay in the stepper type designs. You can get decent steppers big enough for you needs (not as cheap as used/surplus power window motors) but cheaper than full blow servo and matching electronics.

Hang around the list here and look at the table plans from MLAWS1172 on the zone. You need to learn how the pieces fit together and how a drawing can be turned into motion. It takes a dance of software (often several packages), hardware and electronics.

I know you don't think you need precision for what you want to cut, but having something that won't hold better than .050 tolerance will be very limiting as to the type cutting you can do. There have been lots of machines built with angle iron rails and roller bearings. The important thing is to be able to build it so the rails are straight and level (and parallel to each other). You can get V-Groove bearings that will run the 90 deg edge of angle iron. Lots of ways to skin the CNC cat.

Welcome to the Zone and to the fantastic world of hobby CNC. You are in for an interesting journey!

TOM CAUDLE
www.CandCNC.com

[DISCONNECTED]

TRAVIS,check out TORCHEADS products with the link he provided I do not know what your budget is.In my opinion it is alot easier to buy a kit like he sells.Plus Tom has excellent product support if you have problems or have questions.I run a table that uses his torch height control.

[kermit582]

thanks for all the good advice I've been on e-bay alot looking at all the electric parts I need and ran across some kits just wondering if this would do what I need http://cgi.ebay.ca/ws/eBayISAPI.dll?...ype=osi_widget

I would still need software but I just wondered if it would be worth bidding on if I could get a good deal. Any coments would be great

Thanks
Travis
Hawthorne Forge

[kermit582]

thanks for the advice guys. Just wondering if I should bid on this kit on ebay the software is not included but everything else I think is there any comments would be great. http://cgi.ebay.ca/ws/eBayISAPI.dll?...ype=osi_widget

Travis
Hawthorne Forge

[kermit582]

just wondering if anyone ever used a kit from hobbycnc.com before and if is any good. (trying to keep my costs dow)
Thanks

Travis

[millman52]

Originally Posted by kermit582 thanks for the advice guys. Just wondering if I should bid on this kit on ebay the software is not included but everything else I think is there any comments would be great. http://cgi.ebay.ca/ws/eBayISAPI.dll?...ype=osi_widget Travis Hawthorne Forge

In my opinion NO! severely underpowered. You can probably gear them down enough to get movement. But If you check what most people are using the steppers will have at least triple that torque. The round can steppers like the ones listed there aren't even in the same ballpark with the "square" frame motors, especially the double stack motors.

Here is the biggie. You can probably count on NO SUPPORT AT ALL!

[kermit582]

thanks for the advice I went to xylotex and looked they seem to have a good kit there. I'm so glad I found cnc zone you guys are going to help me avoid alot of mistakes. Thanks again

[millman52]

Originally Posted by kermit582 thanks for the advice I went to xylotex and looked they seem to have a good kit there. I'm so glad I found cnc zone you guys are going to help me avoid alot of mistakes. Thanks again

I cut some of my first parts recently & a few more today. It has been an experience to say the least. The mechanical build was pretty straight forward. I first looked at everything I could find, home builds all the kits & prebuilts up to and including ESAB, Kokie, etc. Then decided on a direction to head in. Took ideas I had borrowed from others & had some of my own. Did everything drop into place perfectly? NO!

I did end up with a very workable industrial duty machine & one that will be easy and inexpensive to renew any of the bearing guide rails.

I've been almost a year from an Idea to a working table. I worked on it mostly in spare time evenings weekends & took almost all summer off from the project to Go Fishing with my Grandaughter......

I still have a few bugs to work out & some more to add to the table. & lots of learning in the software area.

Good luck Neil.

[kermit582]

I was just wondering if mach or sheetcam have indexing so you could cut longer material on a shorter table.

[mlaws1172]

Kermit582

After building some and helping on others, the one thing I have found out is buy from those that will support you. This is the biggest cost savings you can get in the long run.

the following is a list of vendors I recommend

1. Gecko Drives - If you blow one up he will fix it or replace it for free. It happens, i know

2. Mach controller software - there is a reason it is number 1

3. Sheetcam - who else would add a feature for you if he can

4. CandCNC - He has all kinds of boards and packages. I think he can put togethor a package with all the above.

I have seen the support these companies give and their poducts are cheap when you look at what you are getting.

Get a hold of Tom at Cand CNC, he knows plasma

Hope I dont sound like I am preaching and I am not selling anything , but the first machine can be a big learning curve. So if you can get the guys that design the products to help (called support), it can make life alot better.

happy cutting
mike

[millman52]

Mike,

I couldn't agree more. I could never have built & get operational, a table without the help of the above mentioned people & many of the guys on CNC Zone, That give so freely of their time to make this a fantastic hobby or business.

Thanks to all

Neil