Worlds Smallest Plasma Table

[msimpson99]

Well, maybe not the smallest, but its pretty small.

The Machine:
I started off with the 18x14 KRMX02 Build. The KRMx02 is a very heavy duty CNC router I designed and wrote a couple books on. It can be built in any of five sizes.

For this plasma CNC build I chose the smallest KRMx02 build size for a couple reasons:
1. It is easy to move around my shop as its mounted on rather large rubber casters.
2. Starting with a small build size I can experiment with many aspects of CNC plasma cutting at a reduced size. Its a lot easier and cheaper to rebuild a small 19x12 table than it is a 48" x 48" table. This was a no brainier as I wanted to experiment with both a downdraft table and a water table.
3. The 18x14 build also had a removable table.

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Wiring
I removed all the switch and motor wiring and replaced them with shielded cable and metal sleeves. In addition, I also added a ferrite core to the end of each cable near the PC. Also note that the cables them selves were placed in a metal conduit from the CNC to computer.

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Later I realized that much of the shielding was a little over done as most of the modern plasma cutters now use a blowback pilot arc instead of high frequency. That said I was able to perform some very cool experiments using my HF start TIG welder with the machine. The HF start on the TIG welder would reset my PC until I did the shielding upgrades.

Torch Mount
The first torch mount was a simple clamp system cut out of Corian and mounted on a piece of extrusion shown here:

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In this design I mount the torch from the rear of the machine.

Later I upgraded the mount to a floating head shown here:

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Please note that with my floating head switch, I do not use it as a limit switch. I have a Z limit switch already installed. I use the floating head switch in the probe mode.

Plasma Table Down Draft Insert

I welded together a simple frame that held the removable slats. It slips between the two cross beams on the KRMx02.

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Down Draft Enclosure

I enclosed the bottom of the KRMx02 with hardy board (cement board).

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I added a 1575CFM blower to the bottom as shown here:

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It is attached to a set of stove pipes that vent to the outside of the shop.

I then added some cleanout drawers:

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That is the basic build to date. I have a writeup on the build here:
http://www.kronosrobotics.com/krmx02-plasma/

I will be posting updates as the build progresses.

[tnbndr]

Nice build and write up

[msimpson99]

This is a pinion gear for a special door lock to my shop. It is one of the first real parts I cut with my plasma CNC. I am very happy with the results.

I also do a test run where you can see the floating head and the probe post processor up close.

You can see the video here:
https://youtu.be/PyfIR_jnP9E

I am still tweaking the settings but this one was cut at 45Amps @100IPM with HF consumables. After cutting I realized the kerf I was getting is actually smaller than what the default was set to .06". The next cut I will set them to .05".

[Capstone]

interesting application and execution. thanks for sharing. I'm giving you about 3 weeks of getting nice cuts and requests from family and friends to make things before you will want to go bigger.

[msimpson99]

Oh, its in the plans to go bigger. Actually, I have several CNC plasma builds in mind. I am spending a year doing research, and will eventually write at least three books on CNC plasma building.

The first will be a detailed addition to my KRMx02 books showing a Step-by-Step upgrade to plasma that will still allow you to use the router. My KRMx02 builds go up to 50" x 102".

I wanted to start small as the downdraft and water tables get much more expensive and complicated as they go up in size.

[Craig]

Good looking rig love the drawers for drop parts retrieval.

[msimpson99]

For those of you who have been following my CNC plasma build, you may have noticed that I have not posted in a while. The reason is that based on my current research with the current Chinese based imports you can only achieve a sub par cut with the current consumables available. Even while some youtube videos will say you can achieve cuts that rival the Hypertherm cuts, I have found this to be pure crap.

I am saving up for a Hypertherm 85 or 65 plasma cutter so I can continue my book research. That said, if the Hypertherm does not stand up to the current claims, I will be reporting on this as well.

It all has to do with the consumables that are available for the particular torch. With the PT torches that are being shipped with most of the more advanced plasma cutters, I have found that they are hard to source the various nozzles and other consumables. This means you are stuck with the default consumables that came with the torch which is fine for hand cutting but really is not up to par for CNC plasma cutting.

The reason I am choosing Hypertherm is because they have consumable charts and a whole range if consumables for various cutting applications. This makes them the logical choice even though the there is a much greater initial expensive involved.