Blasted thing

[Robin Hewitt]

Made another part for my plasma cutter, only took 2 days

4 hours cutting, 12 hours searching though the software looking for a non-existant bug.

Dig ins after the tool change, it went from hole to hole fine, did the roughing out cuts fine, then lost position as soon as I changed tool

Now fixed and waiting for the Araldite to set on the little bits of rod I've put in the nicks

The problem was it took the second tool out at top speed slightly past the cut start and then doubled back on itself to reach finishing depth.

Nowhere else did it do an abrupt about turn, only 0.2mm and not really enough to see what was going wrong, but I was losing steps.

Tomorrow the top of the axle box and THC motor mounting, (unless it has more surprises for me)

[Robin Hewitt]

Radical redesign slowed me down, the THC drive was going to block the vertical slide so I had to turn it upside down

Couldn't bolt the THC motor on, I had bought American type screws to fit the American type motor, even bought Imperial size Allen keys to do them up with. Unfortunately they sent metric Allen keys in an Imperial packet, close but no coconut

The pinion shaft rather stops me fitting the stepper, don't want to saw it off until I have the other end meshing with the rack (which hasn't arrived yet). Saw in haste, regret at leisure.

Did manage the top of the axle box, try to do the THC pulleys tomorrrow.

[Robin Hewitt]

THC pulley box done, now some fiddly bits and waiting for parts

Also I have promised to make automatic window openers for the orangery and I'm being nagged to death so there will now be a delay in making plasma cutters

Rather dreading making the plasma torch carriage, have to get the separation on the rails 100% if it's going to sit square. Don't want to resort to packing, have to think about that...

More when I have it.

[Dale Heart]

That looks freaking sweat. Please keep updating this, it's super nice looking and I just have to see how you do the rest. The only thing I want to say is that instead of using rollers on something so nice, you really should have used linear slides and blocks.

Edit: How is the automatic hight control going to work?

[Robin Hewitt]

Originally Posted by Dale Heart Edit: How is the automatic hight control going to work?

When the arc isn't ready it fires high voltage strike pulses. I called my brother and said, "I want to measure the volts and detect the high voltage pulses so I know when it's ready". He said, "Easy peasy, you want two filters", so I said, "I'll call you back when I have something to measure"

[Robin Hewitt]

Did the torch slide today, pic attached.

The racks arrived. Exactly 1 and 2 meter, not slightly longer as promised. Have to do a quick release so I can change the head consumables

R-TECH rang me looking to sell me a plasma cutter, so I took the opportunity to buy the torch and lead. Makes it a lot easier to design the mounting

Having problems finding copper braid to screen the torch cable in less than 100 meter reels

[Robin Hewitt]

Waiting for metal to finish the torch clamp so I did the driven end of the x axis rack.

Found a lump of hard steel at the bottom of a blind hole in the alloy block, or rather my milling cutter found it, now an ex milling cutter

I balanced it on the end of the cross beam for the pic. It won't go down because I have to profile the beam to fit around the bearing

[Robin Hewitt]

Torch clamp done. Made it quick release so I could change the tips without having to overrun the edge of the plate (thanks Massa)

With AutoCAD and CNC a twelve sided octogon radiused two ways is just as easy to cut as round, so I made it a bit fancy

The idea is to overall screen the torch so I don't get moaned at for interfering with the TV. May be completely unnecessary but sounds good.

[Robin Hewitt]

Forgot to mention...

Bit worried about the torch holder coming loose on the plate and wobbling about when dragging the lead at the top, so I put it on with a push fit double mortise joint.

The bolts are a bit superfluous but reassuring

[DSL PWR]

That is a clean setup!

[massajamesb]

Robin, I have been watching this for a bit, I must say that your work is extraordinary. I am very impressed, keep it up!

[Robin Hewitt]

Originally Posted by massajamesb Robin, I have been watching this for a bit, I must say that your work is extraordinary. I am very impressed, keep it up!

Thanks very much but there is an old saying, the proof of the pudding is in the eating. I won't know if it's any good until I turn it on, hopefully I have remembered everything so it doesn't pick up too many bolt on after thoughts

I'm just trying to work out the track that stops the y axis gantry sliding in the y axis.

All my tracking rollers are sprung so they can ride up and over debris but this one is different because the forces are so much larger.

When the torch carriage moves across it has a max of 156 lbf accelerating it. This falls on a pair of rollers so I want 156 lbf holding them together. Not easy arranging that kind of force (keeping it light weight) without things getting bent out of shape.

If the steel box section bends more than 1.5 mm (0.06") pinions will start colliding with steel end on.

It will probably never ever get the full loading, but still needs thinking about

Top right hand corner in the pic.