It is currently Mon Jun 18, 2018 4:38 pm

 

Trying to wrap my head around DIY table build...

Share and learn with other DIY members who have built their own plasma tables and accessories.
calsdad
Posts: 29
Joined: Tue May 06, 2014 11:51 pm

Trying to wrap my head around DIY table build...

Postby calsdad » Tue Apr 03, 2018 8:27 pm

Looking for some advice and knowledge. I'm seriously contemplating building my own plasma CNC table.

This wouldn't be a huge table - I'd be building either a 4x4 or a 5x5 table . I don't have room for any more than that in my shop.

I've been wanting a table for a few years now. I've looked seriously at PlasmaCam, Dynatorch , and a whole bunch of other manufacturers. I've talked to the local Swiftcut rep and seen one of their tables in action. In the past I've not wanted to go down the road of a DIY table because it seemed like it was going to be hard to put a table together - get the software working - and have it do what I wanted it to do. An already built table with it's software package appealed to me because I just wanted to get the thing up and running and start cutting parts.

Recently though - I've seen a few videos and been reading up on the Centroid Acorn CNC board and it's supporting software:
http://www.centroidcnc.com/centroid_diy ... oller.html

- as well as the Clearpath servo motors:
https://www.youtube.com/watch?v=ZRURwDFvdAs

Found a lot of info on guys using either the Acorn controller or the Clearpath servos or both - and having really good luck with getting them to run reliably without a lot of trouble: https://www.youtube.com/watch?v=4QqVa2lgU7U

The fact that people seem to be having straightforward success with the Acorn board and Clearpath servos is what got the idea of DIY'ing my own table back into my head.

I've got a pretty well equipped shop and I'm sure I can build the table and gantry with no problem - the table is easy, I can either build the gantry or buy a kit from some place and weld it up.

I think I have a pretty good understanding of how to setup the servo motors and get the motion part of this working. I'm thinking that the Clearpath servos combined with ball screws would give far better accuracy than I could get with plasma anyway. NY CNC on Youtube has a video showing the performance of the Clearpath servos and they easily have the power to move a gantry at high inch-per-minute speeds.

The part that has me somewhat confused - is how all the electronic / software pieces tie together.

I want the following features on the table :

Automatic height control
Ohmic sensing
an engraver
tracing functionality so I can trace a part out instead of having to draw it in CAD

The Acorn controller is not specifically meant for Plasma - so there does not appear to be any built in height sensing functionality. There is however a probe feature that could be used to setup a part tracer. It looks like Sheetcam has a new feature where it can scan in parts: https://www.sheetcam.com/Scanything/index, says you need Mach3 though to get it to work

I'm guessing that I'd use Sheetcam as the software to run the whole thing.

I guess my problem is this: before I take the plunge and undertake the project of building my own CNC plasma table - I'd like to understand a little better how all the pieces will fit together and work together. What I really don't want to do is create another year long project for myself.

Are there any good detailed tutorials out there that might help? Any advice anybody can give is useful.

tcaudle
Posts: 972
Joined: Tue Feb 28, 2012 6:47 pm

Re: Trying to wrap my head around DIY table build...

Postby tcaudle » Thu Apr 05, 2018 2:34 pm

Bringing a box full of different products together and making it all work for plasma will be your challenge. Kinda like building a car out of miscellaneous parts and pieces. The tracing module for SheetCAM (Scan Anything) works with MACH OR LINUXCNC. There are as many different ways to build things out of parts and pieces as there are builders that have done it. ScanAnything does not use a Probe input. It uses pattern recognition using a camera and "drives" the table to make it into a Smart Scanner.

calsdad
Posts: 29
Joined: Tue May 06, 2014 11:51 pm

Re: Trying to wrap my head around DIY table build...

Postby calsdad » Thu Apr 05, 2018 2:48 pm

Thanks for the reply.

I figured that would be the challenge - that's why I was asking!

I've built cars before out of parts and pieces - so I'm used to that challenge. The hurdle I have with this is understanding how all these parts and pieces fit together. I've actually been looking into this off and on for the last couple of years - and what turned me off to going the DIY route - was reading about people having lots of issues with motor control. Since running across information for the Acorn controller and the Clearpath servo motors - it got me thinking of going down the DIY route again.

All the information I have run across for the Acorn and the Clearpath servos seems to indicate that they work extremely well and are pretty straightforward to setup and get running succesfully. As an example : there seems to be lots of guys swapping over to the Acorn controller and Clearpath servos for controlling their CNC mill conversions and they're very happy with the success they've had with getting it all up and running without a lot of hiccups.

I've spent some time on the Centroid (Acorn) forum and it appears right now they have mill and lathe specific "Pro" software - and are working on router specific software - which would work well also for plasma cutting.

Being a newbie at this - the part that I'm unclear about is : how do all these pieces fit together? By that I mean - (for example) - in a plasma system what does each component do? Does Sheetcam send G-code to MACH or LINUXCNC - which then translates the G-code into actual movement commands to the motors?

I see a lot of THC addons like Neuron - how do these work in conjuction with say Sheetcam and MACH to control the height of the Z-axis and the torch? Would Neuron control all Z-axis movement or does it work along with MACH (or whatever the motor driver is) - to just control the "fine" height of the torch above the work?

Before I take the plunge on this I'm trying to get a better idea of what I'm getting myself into. I don't want to start spending money and then run into a road block.

User avatar
SeanP
Elite Contributing Member
Elite Contributing Member
Posts: 769
Joined: Thu Aug 01, 2013 11:50 am
Location: Co Kerry, Ireland

Re: Trying to wrap my head around DIY table build...

Postby SeanP » Thu Apr 05, 2018 2:53 pm

I built my own 5 yrs ago and have no regrets at all, I went for the electronics kit from Candcnc, seemed a safer option to me and would do the same again.
There is enough to think about really without trying to do all that.
I got setup with scananything, to be honest I have only used it on one tricky job, it worked but even with a crisp black/white outline you still have work to do on the drawing, I find best way for most jobs is taking a picture square on with a decent camera, scaling and tracing gives good enough results, lot faster as well.
Link to table build in signature below.
Powermax 45 with Duramax torch.
Home built table, Candcnc DTHC 2, Dragoncut 620-4
R-Tech 210 Tig, Jasic 250 mig
Sheetcam, Scanything, Coreldraw X8, Solidworks
Table build gallery

User avatar
_Ogre
Posts: 531
Joined: Sun Sep 15, 2013 4:26 pm
Location: Motown

Re: Trying to wrap my head around DIY table build...

Postby _Ogre » Thu Apr 05, 2018 3:32 pm

for the best product support i recommend sticking with candcnc, mach and sheetcam
you've already had a reply made by a senior partner/owner of candcnc (not sure if i worded that correctly)
you won't get better product support anywhere

so simple even an ogre can do it :mrgreen:
bulltear 4x8 cnc plasma table, candcnc bladerunner w/dthc, hypertherm powermax 65, sheetcam, mach3
laser cross hair for hypertherm torch http://www.plasmaspider.com/viewtopic.php?f=6&t=12508
an ogre smiley :mrgreen: how cool!

DMoneyAllstar
Posts: 66
Joined: Tue Jan 17, 2017 9:11 pm

Re: Trying to wrap my head around DIY table build...

Postby DMoneyAllstar » Tue Apr 17, 2018 2:49 pm

Built my 5x10 table, enhanced a PPLLC gantry to my liking, and then sourced the controls from CandCNC (620-4 Bladerunner w/ Linux CommandCNC). Started making art-n-parts in November on an evenings-and-weekends basis and have made enough $$ to pay for my entire cnc plasma setup and then some. Stop waiting. Build it. It's worth it.

Make sure you have enough air compressor and that your air is clean, dry and oil-free.

Only thing I overlooked was breathing air quality. I have a water table, but still get smoke/steam/soot. Tried my own furnace-blower-air-filter unit, but was only so-so. Ended up with wearing a full-face respirator and installing a 3000cfm exhaust fan/shutter in my 350sf shop. I'll gladly buy a couple extra $100 bottles of LP for heat so as long as my air is cleaner.

tcaudle
Posts: 972
Joined: Tue Feb 28, 2012 6:47 pm

Re: Trying to wrap my head around DIY table build...

Postby tcaudle » Tue Apr 17, 2018 6:40 pm

Over the years i have been doing plasma cutting ,first as a decorative cutting business, then as a controls vendor, I have moved away from a water table and to a properly designed down draft table design. Done right the down draft will eliminate ALL of the smoke and dust, and the debris collects in the pan and is not blown out of the vent. It requires laminar flow air movement that actually cools the super heated air and particles so they no longer are suspended and fall to the bottom.

calsdad
Posts: 29
Joined: Tue May 06, 2014 11:51 pm

Re: Trying to wrap my head around DIY table build...

Postby calsdad » Tue Apr 17, 2018 10:33 pm

Thanks for the responses. I've got the clean air part covered - already have a Champion 7.5hp compressor and a refrigerated dryer. I've just been throwing around the plasma table thing for a while and I go back and forth between just buying - and building.

I'm glad that you mentioned the clean shop breathing air thing though. It's actually a big concern of mine. I really can't afford to have my shop covered with a layer of plasmized metal dust. I park cars and motorcycles in there - and I don't want to breathe the stuff either. Right now I actually do most of my cutting outside when I'm using the plasma cutter freehand or using a grinding wheel. Which is a problem during the winter or in bad weather.

Part of the reason why I lean towards doing a DIY table - is so that I could build something that really has some good dust control - which a lot of the bought tables don't really seem to have.

I've seen a lot of water table setups - and they look pretty straightforward. What I haven't seen though is a lot of downdraft tables - so I'm not really familiar with what makes for a good design for a downdraft. Any sources or examples out there for how to design a proper downdraft table? My other problems would be - a downdraft table exhausts a lot of air - so it would empty the heat out of my shop. Jim Colt has a nice setup that he brings to shows - which has a downdraft that goes thru a couple of big filters - like the ones they put in those welding fume extractors.

DMoneyAllstar
Posts: 66
Joined: Tue Jan 17, 2017 9:11 pm

Re: Trying to wrap my head around DIY table build...

Postby DMoneyAllstar » Fri Apr 20, 2018 9:53 am

You could also do a combo setup similar to what Tom mentioned above, where you've got a downdraft setup plus a water pan down lower to catch the big stuff & sparks. I think Jim Colt uses something like this for trade show demo.

calsdad
Posts: 29
Joined: Tue May 06, 2014 11:51 pm

Re: Trying to wrap my head around DIY table build...

Postby calsdad » Fri Apr 20, 2018 10:41 am

Keith Fenner on Youtube has a combo setup on his Plasmacam . He's has that Plasmacam in a relatively crowded shop - so it must keep the dust down to a manageable level. I looked at the Jim Colt setup and ran across some posts from him after my last post above. Jim said that his water table is something like 6-8 inches below the material bed - and then the downdraft pulls higher up to get the remaining fumes. The water table gets most of the pollution coming out of the cut - and the downdraft suction takes care of the rest.

I guess my sticking point is: I haven't seen any good materials on how to design a good downdraft. I read a lot about "laminar flow" - but haven't seen any good info on how you achieve that. There must be some ducting strategies that would work to get equal suction around the whole table. Guess I'll have to do a little more research.

srp
Posts: 180
Joined: Wed Sep 23, 2009 8:54 pm
Location: Midcoast Maine

Re: Trying to wrap my head around DIY table build...

Postby srp » Fri Apr 20, 2018 7:00 pm

You will not know the damage you are doing to yourself until years later and when it is too late. This is a nasty business and the dangerous elements are the ones you don't even see. When you exhaust air from your shop the same amount of makeup air comes back in. Having worked designing ventilation system the direction of the exhaust stream and the makeup air stream are critical. Breathing people need to have their heads in clean air. This is where the design is important. Visualize the flow of air in your shop and layout a system which keeps the people in the clean makeup air flow. In my current shop I accomplish this with open windows and floor to ceiling curtains. Yes you will be sucking the heat or a/c out of your shop. I wear insulated coveralls in the winter and still the shop never gets too cold to hamper machine or me and I live I Maine. Bear in mind the most damaging element that will affect people the most is not the visible smoke particles but the invisible aerosols which are not filtered out by particulate filters. You have exhaust them.

calsdad
Posts: 29
Joined: Tue May 06, 2014 11:51 pm

Re: Trying to wrap my head around DIY table build...

Postby calsdad » Fri Apr 20, 2018 9:55 pm

Part of my problem is that I'm in a suburban neighborhood. So I can really be sending a plume of plasma smoke out of my barn without standing the likelihood of peeving off my neighbors. I also don't want to be coating all my vehicles and my own property with plasma smoke. Looking at the fume control on a lot of the consumer level plasma systems out there - is what got the idea into my head a while back about building my own table. I was thinking that if I started off from the get-go with the idea of fume and spark control ( watching these things I noticed that sparks go shooting out quite frequently too) - might let me design a table that really keeps both well under control.

I have a Lincoln Mobiflex 200M fume extractor that I picked up a couple of years ago for a really good price. I had been doing a lot more MIG welding - and I noticed that I was getting a lot of fumes out of it. The fume extractor sucks the air directly over the welding area - runs it thru a large filter - and then exhausts back into the room. So it doesn't suck the heat out of the room. I've read that they do not recommend using the same type of filters in the fume extractor for sucking in plasma fumes. I haven't been able to track down exactly why that is though.

Jim Colt has a setup on the small plasma table setup that he brings to shows that has some integral filters. I saved the info somewhere on who made the filters - just can't find it at the moment.

I'm wondering if my end solution might be some sort of solution with both water table and downdraft - where I run the exhaust air thru some filters before dumping it outside just to make sure I've gotten rid of all of the particles (but filtering it first to make sure I'm not dumping a cubic ton of junk outside).

The loss of shop heat during the winter bothers me a little - but when I get things finally fully up and running I'll be running radiant floor heat in the shop so the heat loss problem isn't as big an issue as it would be if I was using forced hot air.


Return to “DIY Plasma Table & Accessory Discussion Forum”

Who is online

Users browsing this forum: No registered users and 1 guest

Easyscriber engrave attachment for Hypertherm torch's