The bed will need to be replaced before we are able to put it back in operation we will start looking for a replacement ASAP.
Sorry for the delay in getting a new pan. Life gets in the way of volunteer work. Still working on getting the dimensions correct so we can order it.
The two main issues with our current design are edge splash from the table getting between the pan and frame. Dissimilar metal corrosion.
One thing we should change is the way the grounding is applied. we have 3 base supports for the slats. With a strap on one base bar. In theory the slats on the first bar have many contact points that should electrical connection to the bar. If as things get dirty electricity will find the path of least resistance. That might be from bar -> pan -> bar. I think it would be better weld grounding strap on each slat base wire them directly together.
Second some have floated some sort of coating. I don’t think that is needed since it will be scratched in this environment and lead to point corrosion where the points are exposed as apposed to the entire galvanized pan surface.
I think a better solution would be to insulate the underside/sides of the base where they contact the aluminum frame with rubber flashing tape. Also insulate the base of each slat with the tape. This would also protect the galvanized coating when removing the slat bases.
And a 90ft roll of rubber flashing tape is about $25. Peel stick done.
If anyone has a better solution, or can poke holes in my views pleas do so.
The pan should be ready to pick up by wed.
I am going to go down to the metal shop tomorrow to do some cleaning around the plasma table. If anyone would like to help out. I think I am going to start about 11 am.
Good news I picked up the pan. It is on the table full of water just to verify it still holds water after being shoe horned into the table. Take a good look it will never be this clean again.
I need to grind down some tall spots where it is taller than the sides and could be a bit sharp.
There was a bit of a miscommunication between me and the manufacturer, so there is a seam running down the table, so we will have to offset the center base, but I don’t see how it will cause any problems. The side benefit is that it is a thicker gauge metal than before, so in theory it should last longer.
I will check that everything is dry tomorrow. I will need to drain the pan, and address the edges. I still need to fix the broken torch mount. My plan is to work on it over the weekend and try to have it back online Monday.
I need to rework the grounding straps and I would like to address the gap between the pan and the table. Tons of water and cuttings makes its way down in places and sits there an corrodes the table.
I did drain the muck barrel. The clean water is in the table and the rest of the muck is in the buckets under the table. It could use a bit more rinsing. But there is a limit to the number of evenings in a week I can go home completely covered in metalshop muck. I will give it a week to see what settles out. Then we can decant the water.
I wonder if there’s something we can add that would cause the suspended particulates to clump up and sink to the bottom? Any chemistry students (with passing grades) on the forum?
Today Tom R. and Myself worked on the table. Tom R. drained the non leaking pan. Yah.
We cleaned up the 3 slat bases (thank you Tom R. for removing all of the rust with the wire wheel). We covered the base and sides of the pan with rubber tape, to try to isolate galvanized pan from the aluminium structure.
We installed 3 new beefier grounding straps, one on each base. The plan is the wire all 3 slat bases together with 10 gauge ground wire. I would hope better grounding would help with cut quality.
We checked the height to the pan and ground down any sharp point that might catch things, and did a bit of grounding.
I moved the slat bases around on the table. This was prompted because of the seam in the pan made it impossible to have a slat down the middle, but after trying to get all of the slats to fit, and sit flat I noticed a large amount of metal removed where they had been sitting on the base. So the asymmetrical arrangement should allow multiple slat movements with each cleaning. this will allow better utilization of the slats. and have a more uniform table.
After sorting out the arrangement I spent some cleaning out the groves and pounding down the slats into the groves.
Good new is I did not cause any leaks. Bad new. After reviewing the water level. The table is not sitting flat. What is worse one of the legs seems to be 1/4 inch high, so I will need to re level the table. This might help with the binding that is causing a loud sequel from the ball screw. I hope I can re-level the legs without draining the table.
Here is a picture of the table with water. Even if it is leaching yellow rust in to the water it is at least one step closer.
I also condensed the water buckets, so we have 3 buckets (15gal) of water that can be put back into the table.
Phase 1, Tomorrow hopfully
Finish wiring the ground straps. I have drilled the holes in the ground bars, and crimpted the connectors on the 10 gauge wire.
Replace Air filter (tp roll).
Level the table.
Replace broken and sloppy torch mount. Improve it time permitting.
Test water in table/buckets to establish level of remaining rust inhibitor. Establish schedule for adding additional rust inhibiting chemicals.
Find and fix dying fan on table power supply.
Add cover to the electronics.
Establish easy table cleaning procedures.
Add filter to table to keep it cleaner.
Tom R. Explore options or adding sheet metal splash covers to keep water/grit from getting between the pan and table structure.
Phase 3 (nice to have)
Upgrade to new version of linuxcnc.
Add second limit switch for second gantry.
Test Torch height controller.
Rework pc to lock down pc and reset configs each reboot.
Stiffen gantry mounts. to reduce flex. This should allow acceleration of table to be increased and provide better cuts.
Thanks Tom B. And Tom R.!
And thanks for keeping everyone updated!
I go through a few more things tonight, but while changing the filter and checking things out. I found corrosion on the inside of the filter causing the powder coating to flake off. That will need to be sorted out before it goes back in service.
Can I get a volunteer to swap up around the plasma table? I moved the barrel and scrap around the table. No need to mess with the buckets under the table, just the sides and back. It will help out a lot.
The test magnet only mount was just as floppy as before even more magnet surface area and non skid coating on the magnets. I bent the aluminum flanges inwards so they make contact with the main z plate. The floating plate still moves, but it reduced the side to side play. It is better then it was before, but still needs work. Don’t make fun of the zip ties. I did not have the time to print a solid cover, when this was only to test the magnet arrangement.
good news. the air filter has arrived. Thank you @David for ordering it. I have funeral to attend Sat morning, but I might be able to come in to finish things sat evening.
Sunday is out for me.
I also need to adjust the z probe height.
You have my number
I was not able to make it down to the space today to replace the air filter. Stupid tree limbs. They don’t cut the selves. I can come down tomorrow night. I think I should be done about 6pm. I will for sure hook the computer back up and try to swap the air filter.
If Josh @heathenfire79 is ok with someone else swapping the housing it would help me out a bit. I am a bit tight on free time this weekend. If there is any one that is capable and willing to do some minor plumbing to swap the air filter housing tomorrow before I get there. Then I can get right to hooking the computer up and testing things. I did not install it originally, but I assume it should not be too difficult. I think it is https://www.northerntool.com/images/downloads/manuals/490500-2.pdf
I don’t know if there is any ptfe/teflon tape for the fittings around the space.
ill go ahead and get that done
Its finished. Housing has been replaced, threads re-tefloned, and leaks checked. All good to go for you tomorrow. All of the spare parts and whatnot are ontop of the plasma cutter