Again, another feeder design

[Knas]

If there is interest it might be smart to outsource a few parts.

Case can be 3d printed, the "flat" metal parts can be laser / water jet cutted.
The gear needs to be machined? Of course there should be some kick back to the designer. This is probably still in beta so there is some acceptable risk.

Actually, the main gear is two gears cut as one in the current design and could not really be laser or plasma cut, they could potentially be made into two pieces and put together as one though. 3D printing of the case would work but it'd probably be a *lot* slower than cnc routing. Really injection molding would be the ticket here i believe for fast manufacturing. However i would still recommend doing the case in several parts as the modularity for tape widths is out the door otherwise. I've made 12 and 16mm casings too but i think i will design a 4mm "adapter" instead so that they can be truly modular. The one problem i haven't solved yet is how to make one design work for both paper and plastic tape, plastic requiring a different tape shelf height.

[Spikee]

make a mould and use polyurethane for the casing. Works great.

mould can be wood , plastic or whatever

[mrandt]

You can find downloads and a writeup here
http://www.knasmusic.com/diyeverything/ ... eeders.php, gerber and STL files for the 8mm paper feeder can be downloaded at the bottom.

Hey Karl,

I downloaded the files and had a closer look. The ZIP seems to contain GCode (*.ngc) and STL - but no vector format I could use to make a 3D model or convert to other CAD format.

Could you please share the source files? If you use CamBam, the *.cb would work fine; I can use the evaluation license of CamBam to export into a suitable format. Otherwise DXF or SVG would be great.

Thanks
Malte

[WayOutWest]

Can I ask you one more favor? Could you post two pictures of the Juki nozzle (connector side) - one with nozzle pushed in (spring compressed) and one in "normal" state? I am curious how these babies work.

In case Knas never got around to this... my nozzles and holder arrived today. Here are the pictures you asked for (taken with my needlecam, because I'm lazy). The cap in the foreground is an 0603 for rough size reference. Second photo is with pressure on the needle tip. Third photo looks down the shaft of the holder, which has a tiny rod across its diameter -- perhaps this is to keep the sensor from being sucked up the vacuum tube?

I did realize why the coupling is so long though -- it's EXACTLY the length of a Misumi LHFC10.

4.jpeg (85.98 KiB) Viewed 7670 times

5.jpeg (118.63 KiB) Viewed 7670 times

6.jpeg (158.11 KiB) Viewed 7670 times

7.jpeg (122.23 KiB) Viewed 7670 times

I just rembered reading about that somewhere a while ago and finally found the source again:
http://stephanschulz.ca/sts/howto/slipring.html

Neat trick, thanks for posting!

How do you do z-min (i.e. hitting the table or PCB) detection? The original liteplacer depends on a "stiff" pickup rod to trigger the limit switch, but the Juki nozzles seem to have a built-in spring that would absorb the pressure. Do they have some kind of sensor switch in there?

Karl described his solution before - he is using a electric contact inside the nozzle holder in a true hacking style

Check it out here:
http://liteplacer.com/phpBB/viewtopic.p ... t=10#p1292

Nozzle tip needs to be grounded. A slip ring (or electrically conductive ball bearing) could be used instead of steel wool to make reliable contact to the rotating contact pin - but then it should work fine.

Another option would be to put a longer plastic or metal pin inside the nozzle holder and us a piece of transparent tubing somewhere upstream. We could then use optical sensor to detect that pin's appearance / movement along Z-axis when nozzle spring is compressed.

A third option was introduced by jarekk - he uses 3D printed discs and a capacitive sensor:
http://liteplacer.com/phpBB/viewtopic.p ... =192#p1324

Hrm, I get it, but I don't have anything like Knas' "swiss cheese" HDPE, nor a 3D printer (*)

- a
(*) actually I have one that's still in the box, but I don't dare open it for fear that it will turn out to be as fascinating and all-consuming as the liteplacer has been.

[jarekk]

>> Really injection molding would be the ticket here i believe for fast manufacturing.

My plan is to use plastic moulding as well.
I do have this one: http://www.travin.co.uk/tp1.html
I will make myslef cheap moulds ( from precise aluminium blocks ) on my CNC

[WayOutWest]

Hrm, I get it, but I don't have anything like Knas' "swiss cheese" HDPE, nor a 3D printer (*)

Ah, got it now. Found a tiny set-screw and inserted it into a plastic tube, inserted the plastic tube into the nozzle holder, everything works nicely now.

The metal part of whatever you put into the shaft needs to be considerably smaller diameter than the shaft itself, otherwise it'll be always-triggered as a result of contact with the outer collar of the nozzle. An M3 (I think) set-screw inside a ~4mm-diameter plastic tube seems to be the right combination.