Finally, first pass prototype build

Finally!

So, finally got a working prototype build.

Things still to address:

• The mounting holes were not far enough apart to fit the frame of the manual pnp. No problem, as the OpenSCAD file is parameterized for that!
• Takes too much “help” to advance the wheel. Sticky. I think this is just axle spacing of the “friction wheel”. That did have a smaller adjustment than the “lever”.
• Might opt to cutting off the pin that is used to drive the tape. It doesn’t seem to print consistently, because it’s so small and because it’s jutting out and relies on rely fine precision and dang good luck. Just needs a fine drill and maybe some nylon fishing line or something. That trick is used in another feeder design so seems to solve the problem, though likely fiddly and error prone itself.

Crap!

Arrrggghhhh!

So, forget the “snug” setting. It does not adjust for this problem.

So, I changed:

reel_axle=13

to:

reel_axle=13; // [13:0.1:14]

So I set it to 13 to generate STL for the “friction wheel”, and bump it up a tad when printing the “spool left”. Since the value is used for both.

You could do something like:

reel_axle=13; // [13:0.01:14]

The point is instead of having a HMI widget scrolling whole mm, you can scroll part there of.

That line of code is sitting in the PushPullFeeder.scad file at this git site.

I also had to do something similar with the:

tape_inset_begin

tape_inset_end

To tweak it since the tape inset would not fit the body as the mating section was too short. The mm “tuning” of either one end or the other would move the whole inset one direction or the other, and best you could do was either 1mm or 2mm change in length, whereas a finer tuning to also keep the inset in the same spot seemed to make more sense.

I am not keen on green

Try, try, try, try, … , again and again and again.

Compromise

So, I am not liking the green filament. Not fan of the colour, but opted into it as a homage to designer.

Not a fan of the green filament, it is, for some reason, a pig to print with.

Finnicky about sticking to bed. Changed temp. Speed of first layer. Laid down sticky stuff.

Mating all the parts up is such a chore. Worked out the tweaking for “axle” seems arse about. It actually is on the “holes” not the “axles” per se. So, a negative value was making the “holes” smaller not bigger as was required.

Test print a dud. Used the test print to find, apparently, my printer needed axle parameter set to 0.16. Pieces did not fit at 0.16 nor 0.18 so I am trying a 0.40 axle setting at the moment, on the friction wheel as the test piece, since a 0.25 axle setting was probably just on the borderline of actually looking half way like it might be force pressed on. NOPE. Had to try 0.50, now it seems snug but not tight.

Opted for the flat screw down instead of the extrusion fitted. The parameters include spacing of the holes. The compromise is then go without the fang dangles. The photo is before I found the parameters for the holes. They are 30mm apart but need be 40mm apart to fit to the two 2020 extrusions that the original feeders fit into. A nice compromise. Just now ordered a 100 pack of M4 x 8mm counter sunk from Aliexpress, but will get a smaller pack of same locally (for oodles more $$$) to have some for the trial fittings.

Too many variables

So, still on this feeder option.

I tried print runs of the test pieces with the white filament. 3 runs and I still had problems finding tunings to allow the clearances for fitting let alone smooth operation.

So I have a bunch of miss-matched parts that don’t fit together.

The tuning seems to be per spool so might try test print with the green. But then it does it make sense to match the white axle with the green bearings?

Seems quite fiddly then to tune to get a working feeder, let alone a batch of 8mm and then on to wider feeders.

So, I’ll opt for a single colour and start with green 8mm.

I’ll report progress against tag “PushPullFeeder”.

It’s not easy being green …

… at least green 1.75mm PLA from FlashForge.

A mentioned in entries earlier, I opted for this feeder.

I got over my ickiness about green filament. But have had all sorts of problems printing it.

Finished my while reel, not to mention the run with red filament for the incumbent feeders for the PnP. No problems since the rewiring with the new flat cable and board on the extruder.

But this green filament?! A number of blockages and therefore failed runs. Obviously I had to unblock the blockages.

So when I contacted FlashForge, they were very helpful. They told me to unblock the blockages.

So I made a number of unblocking of blockages and then the gem appeared to be use 200oC and not 220oC?!

Of course, that meant I could not get the rotten print to stick to the bed. So I am trying with 205oC but not sure why dropping the temp helps. We’ll see. Print underway.