El Beast - Initial design phase, comments and critique welcomed!

[Zeeflyboy]

Cheers, yeah I was thinking of adding holes to allow a bar to help tighten it up.

So my wife gave birth to a happy little baby boy last weekend, which has as you may have guessed been consuming most of my play time! I haven't been able to do any milling but I have made a slow start on my anodising setup. I did a lot of reading up over the past week or two about LCD anodising method, and I've decided that the first thing I want to tackle is the anodising tank itself.

I bought a large polypropylene crate (just look for a number 5 and the letters PP) at homebase, which is big enough to fit the largest pieces I want to anodise at a little over 600mm long.

Problem is that I couldn't find anything with the length or depth required in a narrow width, so the crate is about 80L, probably 60 or so when filled to a level that I require. That's a lot of sulphuric acid, even if it is very dilute when using the LCD method. Seems that the recommended concentration for 6 ASF (amps per square foot) is 1:15, so I will need 3-4 litres of sulphuric acid to mix with 60 or so litres of water. It's also going to be very heavy, so my plan is to build a wheeled wooden frame around this crate to support it and make it easier to move around. There are definitely some logistics to consider with this much acid around and I may end up storing the solution in some appropriate plastic drums when not in use to keep things a bit safer.

To help keep the solution cool and with the happy side effect of displacing some volume from the tank thus reducing the amount of acid required I have made a PVC pipe system that I can pump cold water through to help keep the temperature down. Made using 32mm pipe and chemical welding






Next up will be the cathode bus bar and cathodes. From my reading Aluminium cathodes are better than lead in several regards, and means I don't need to worry about eventually disposing of lead contaminated solution.... but it seems the type of aluminium is quite specific for the best results. 6063-T6 is the specific type recommend, and I managed to find some fairly large extrusion in that formulation.

So far I have just cut up the pieces, the angle extrusion will be bolted to the square bus bar using stainless steel bolts (will be above the solution, not in it).

I am also considering my options for agitation. Easy one is air bubbling, but I've seen a few using acid-proof pumps to move the solution around which seems like a better option and would give me a mechanism for pumping the acid out into drums for storage and vice versa.

Anyone who has any experience with anodising I'm always up for helpful info given I'm a noob.

[1Jumper10]

That contraption looks a little bit like a baby crib. Dont accidentally anodize the newborn :)

Congrats!
Watching your build log with interest.

[Nickhofen]

Congratulations for the new member!

[Zeeflyboy]

That contraption looks a little bit like a baby crib. Dont accidentally anodize the newborn :)

Congrats!
Watching your build log with interest.

That would certainly be one way to get into the newspapers....

Cheers chaps!

[Boyan Silyavski]

I used 6mm size tubing , remember also the aeration, is really important to move the liquid.

[Nickhofen]

I used 6mm size tubing , remember also the aeration, is really important to move the liquid.

From the baby?

[Jonathan]

Anyone who has any experience with anodising I'm always up for helpful info given I'm a noob.

Don't underestimate the amount of de-ionised water you need. You have to use copious quantities of it at every step to keep the parts clean, else you'll see white deposits appear on the parts at the end. The deposits sometimes polish off, but it's best avoided ...

[Zeeflyboy]

Yeah I'm guessing as Boyan suggested it may be worth getting a reverse osmosis setup... can use the water in coolant mix too (and the iron ;) ).

Desertboy - cheers for the offer. Sulphuric acid is a bit more of a bitch than most acids as it's an oxidising agent. Seems many plastics just can't deal with it so you have to be quite careful about what you put in it... Not so bothered about damaging a pump, more bothered about contaminating the acid.

most DIY kits seem to just use air agitation and an aquarium pump to supply the air. We'll see whether the budget can stretch to a decent pump next month!

[Zeeflyboy]

Back to the build!

So had a chance to make my rail alignment doohickeys:










My plan to cut them so that the critical height is on the same part of the ballscrew seems to have worked well:

13.499mm



13.500mm




Biggest variation i found was 13.497 to 13.503, so max variation of 0.006mm (0.00024 inches if you are that way inclined), so pretty happy with that.


I 3d printed a jig and made some drill bushings on the lathe, looks like a shocked robot:



After drilling, tapping and a quick de-burring I gave the 20mm bed plate a good clean and laid the machine down on it upside down. Wiped each piece and area with an alcohol wipe to try and minimise any dust or dirt before fastening the rail spacers into position against the bed plate as a reference.





Then finally gave the rails a good wipe with a vanguard anti-corrosion wipe (hopefully minimise any naughtiness between the steel rail and milled aluminium mounting surface) before mounting them against the rail guides.




Next up will be re-making the front plate after my motor mount height snafu, then I can crack on and get this lower frame finished off before moving on to the Z-axis next.

[routercnc]

Good work Zeeflyboy. Like your thinking - in the absence of a large surface plate (£££) you've done the next best thing.