Tape Strip Holders

[hendrik]

I know I'm late to join this discussion, but what about a threaded hole in the bottom plate, then insert an M3 setscrew with some red (permanent) loctite. Now you can use a thumb nut, and I'm very sure you won't lose the setscrew. No trouble with press-fit screws, no trouble with a screw coming out through the bottom.

[JohnSL]

Hi Henrik, I've been following your build progress on the OpenPnP forums--nice work.

I know I'm late to join this discussion, but what about a threaded hole in the bottom plate, then insert an M3 setscrew with some red (permanent) loctite. Now you can use a thumb nut, and I'm very sure you won't lose the setscrew. No trouble with press-fit screws, no trouble with a screw coming out through the bottom.

Using a threaded stud is a great idea and very easy to implement. I'll have to try both methods and see which works better.

[instrukcion14]

and btw what about using wafer head screw instead o classic screws (looks much better)? on ebay you can find 100pcs which cost about 5usd and on aliexpres i found 1000pcs for 20usd. perhaps is also possible to use M2,5 or M2 instead of M3. My idea.
http://www.ebay.com/itm/M2-Head-Dia-5mm ... nzN1aEb3BA

maybe it can allows you to do plates much thinner.

[hendrik]

Hi John,

Hi Henrik, I've been following your build progress on the OpenPnP forums--nice work.

I'm Hendrik, and I don't have anything on the OpenPNP forums. Different guy. But I agree, he's building a nice machine.

[JohnSL]

Hi everyone,

I've been somewhat quiet because I've been waiting for quotes on injection molds. I just got one quote from a company here in Washington state that was a lot higher than I expected. Based on previous experience from about 10 years ago, I was expecting the molds to be in $5,000 to $10,000 range, as these are very simple molds to make. The quote came in well above that figure. They also quoted about $3.00 for a set of parts, which seemed quite high. I think a lot of this was because of the material they chose. I asked them for an anti-static plastic, but they asked me to supply them with a source. I found one source of information, and apparently that was a pretty expensive material.

I have no connection to the company, I just have them bookmarked for some possible projects for my own business. http://www.star-prototype.com/

I've also requested a quote from Star Prototype, and they said they should have a quote for me on Monday, so we'll see what they come up with. I asked Star Prototype for an anti-static plastic and they said no problem and asked if ABS would be OK. Since I wanted ABS, that fit perfectly.

I have no idea if the market is large enough to support the those estimates, so I've been looking into other options. I have an injection molding machine I purchased via eBay a few years ago but never got running:

PC102145_500.jpg (41.08 KiB) Viewed 18356 times

This is a Simplomatic PRO63, which is billed as supporting semi-automatic as well as automatic molding. It supports much bigger molds than my other machines. I don't know a whole lot about this machine as it didn't come with any documentation. However, with some searching, I've learned that it has a 7,000 psi injection pressure, 6 ton clamp, and 1/3 ounce injection capacity.

The largest part requires 0.26 ounces of material, so we're within the specs of the machine. The surface area of that part is 4.62 square inches, which means that at the 6 ton clamping force the maximum injection pressure I could use would be 2,600 psi if I've done my math correctly. I think that will work. I have another injection molding machine that I've used for "larger" parts I've made: http://www.travin.co.uk/tp1.html. On that machine I've made some parts with a surface area of 4.9 square inches, but only 1 mm thick (sorry for mixing imperial and metric). For these parts I had to bolt the mold halves together because the clamp on the machine wasn't strong enough (I think it's a 4 ton clamp if you have everything set up correctly and use a lot of muscle to close the clamp). I also know that thinner parts require more injection pressure. The larger parts for the strip feeder have a nominal thickness of 2 mm, so should require less injection pressure. The Travin could probably make the parts, except for one issue: the Travin supports 4 by 3 inch molds, but these parts are about 5.5 inches wide. I think the PRO63 should have no problem at all making parts.

The other issue is that I need to use pre-colored plastic pellets because none of my machines have screws. Most injection molding machines uses screws, which allows mixing the plastic with additives like colorants or anti-static material before injection. But I don't have that. Or do I? It turns out I have a filastruder kit that I never assembled, and it does have a screw. So my thinking is that I could use this to mix raw ABS with colorants and anti-static additives to create the correct material. And, instead of producing a roll of filament, I could easily add a "cutter" that would cut the filament into small pellets while the material is still soft. Then I can use the resulting pellets in my injection molding machine.

So, I have two questions. First, does anyone happen to know more about the Simplomatic PRO63 machine? Second, any suggestions on other companies to contact about injection molding?

[martin123]

Hi,

have followed this thread for a while now, I think this looks really promising.
Found some old 3d files, are the latest version available for download?

Martin

[JohnSL]

Found some old 3d files, are the latest version available for download?

Hi Martin,

If you're referring to these files: https://www.youmagine.com/designs/smd-t ... -16mm-24mm

Those are the current files. This thread is about a new design that will be injection molded and for sale from LitePlacer.com. I haven't made those files available as they're not meant to be 3D printed. I have 3D printed some prototypes, but they're rather tricky to print and the 3D printed results aren't the same quality. Once injection molded they'll be much better.

Speaking of that, I'm currently working on the injection molds and will be sending out an update soon.

[JohnSL]

Hi everyone,

I've been working on designing the molds using Fusion 360, which I'm just learning. For those of you interested in the process, I've decided to document it with videos. Here is the first one: https://youtu.be/viwbxM6F7zc

Hope you enjoy. My next video will be making the first mold half. And then after that I'll have a video showing my attempts to injection mold them with my machine.

Thanks,
-- John

[instrukcion14]

how does it looks like with this feature?

[JohnSL]

Just a brief update. I've been making progress on the molds, and will probably have the first mold finished this weekend. Here are a couple more videos:

https://youtu.be/6RhDVkQHMBk

https://youtu.be/FEu1IphApxw