Little boxes all wrapped up in ticky tacky !

[awemawson]

I needed a small box (6"x3"x2") to cover up the back of some control buttons that was adding to the Traub lathe. I bent one up out of 1.6 mm zintec steel but I wasn't at all happy with it as I couldn't get the bends sharp enough

[awemawson]

OK it would be behind a panel so couldn't be seen - but I'd know it wasn't right!

I've previously run an angle grinder with a 1 mm disk along a line to bend tight bends, but this was a bit too small for that approach  so I thought that I'd update the idea with CNC.

I drew up the box profile and bend lines in FeatureCAM, stuck the target sheet down onto a backing board with double sided tape and unleashed the Beaver Partsmaster on it. Profile was done with a 6 mm end mill, and the grooves for bending with a 6 mm ball ended mill.

As the box mounts on the rear of the control panel by screws in two tabs, these tabs needed to be bent in the opposite direction to the rest of the bends involving reversing the sheet part way through machining. I used the holes in the tabs as locators for pins (well actually 5 mm drills!) to get the sheet back in place.

[awemawson]

So all that sounded REALLY EASY !

Well in essence it was, but a lot went wrong along the way. Initially I used a piece of MDF as a backing board, and stuck the sheet down with double sided tape. As the MDF would swell with coolant I had to run dry. The sheet got warm, the tape let go and the emergency stop button got pressed 

I tried again with much smaller increments of cut, but again off she came. This time it wasn't a heat effect, but I had cleaned the backing board with spirit to get the old tape residue off, and although I'd dried it well with an airline there was enough held there to soften the glue and release the part. That was yesterday. In the middle of last night I had a brainwave. Use a bit of melamine covered mdf. The spirit won't soak in.

So this morning I sliced a bit off the plinth of our kitchen units I found some left over plinth board from our kitchen build, and started again. All went swimmingly until I decided to use compressed air to clear chips and keep things cool. As I wafted the air nozzle around it lifted a thin transparent protective cover sheet at the edge that obviously is intended to be peeled off after installation. So my double sided tape is just gripping onto this thin sheet 

In practice it held, I got through the first side, and in fact the peel off sheet made clean up easier for sticking it down in reverse
 

In all a very useful exercise as I've learnt a few things and ended up with a satisfactory box

[Chuck in E. TN]

Nice work!
Chuck

[dsquire]

So all that sounded REALLY EASY !
.
snip
.
Well in essence it was, but a lot went wrong along the way. Initially I used a piece of MDF as a backing In all a very useful exercise as I've learnt a few things and ended up with a satisfactory box

Andrew

Another case of the journey being as enjoyable/rewarding as the destination. Nice work. 

Cheers 

[vtsteam]

Excellent! 

[NormanV]

I did a similar thing to fold 3mm Perspex for a university project except that I used an end mill angled at 45 degrees to give 90 degree grooves. I then heated the Perspex to fold it up into a square tube. It turned out very well. (I got an "A")
Norman

[awemawson]

Thanks for the kind comments chaps 

So flushed with the success of the little box I thought I'd have a crack at one that's been outstanding since I got the Traub CNC lathe. The 'Automatic Oiler' has a plastic cover that was broken before I got the machine. Manufacturer and his agents all have failed to produce a spare.

I had intended to patch it up with gaffa tape, use it as a mould for Plaster of Paris, and when the lump had set use it as the form for my vaccum moulder. I even got the P of P, but hadn't tried as I've always had problems pulling down the hot sheet on such a relatively deep form.

So why not try the new box making technique - well I did and it's a complete success  The box is cut from 1.6 mm galvanised sheet on the CNC mill, bent by hand, then soldered with the new 'lead free' plumbers solder. This is about the only good use I find for the 'lead free' solder. It's harder than 60/40 lead/tin, and solders galvanised very nicely - stays fluid too long though.

[Pete W.]

Hi there, Andrew,

Are you going to move the circuit diagram over?  Aerosol label remover might release it from the plastic box.

[awemawson]

Pete certainly that is my intention. I had a tentative scratch at it earlier and decided it wasn't the thing to do in a hurry. I may well chop up the old box to aid it's removal. However inside the oiler is it's installation booklet which has the same diagram, so I may just scan and reprint it. Mind, it's (not surprisingly) saturated with oil.

[awemawson]

Diagram duly transferred Pete! Left it soaking for a few hours in 'cigarette lighter fluid', and off it came, as did the foil warning sign on the outside pointing out that there were volts inside!

Cleaned them up and stuck them back with double sided tape as it was still on the table from cutting the plate for the box!

[krv3000]

a job well dun