Ejector pin grinding fixture
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- Опубликовано: 1 окт 2024
- Hi Folks, this week I show you how I made this ejector pin grinding fixture. I use it to grind a bunch of ejector pins, which are used in plastic injection molds, at the same time and the same length.
Enjoy!
Two possibilities for small improvement. First, mill pockets and epoxy a little rare earth magnet underneath each v-groove to hold the pins while assembling. Second, turn the vise at a slight angle so the pins spread across the stone, save all that work with the Y.
Thanks Bill, Yes good idea on both tips. I may try to sell this fixture with the magnet idea and the setscrew idea that Vincent mentioned with fancy color anodize. Thanks for watching!
If you want a proper solution for clamping the pins despite the bow, I'd suggest putting 12 holes for small (possibly brass-tipped) set screws in the top that press those pins into the v-grooves. Since you got many allen keys anyway, you shouldn't have trouble finding the right one.
Thanks Vincent, I will add your idea to the fixture, Bill mentioned adding magnets too. I should add several different set screws sized to each groove to improve my hex key chances too
how much do you feed the wheel into the parts on each pass?
About 0.001” per pass in general. Thanks for watching!
For such cases when i need to keep something from rattling i tighten them through copper adhesive tape. Works great.
Thanks for the tip!
@@DragonflyEngineering you're welcome :) Thank you for sharing your work it's inspiring (i know it may sound cheesy, but when i see someone succeeding in his tech projects and endeavours i get pumped up too :)
Put a piece of copy paper under the top cover. That will take up any deflection of the top plate. The pins in the middle may be slightly loose.
John McNamara thanks, good idea. I will try it out probably this week!
@@DragonflyEngineering Copy paper has a very consistent thickness I often use it to hold rough parts in the vice as it serves two purposes. 1 protecting the vice jaws from scratching and 2 improving the grip.
Do not reuse it! a fresh piece each time.
An alternative is to pre bend one of the clamping plates to ensure the centre ones are clamped first.
@@bostedtap8399 good idea
"Loupe" means "magnifying glass" in French (think pink panther cop), I guess that's where the name comes from in English.
Load them all in the fixture at full length, then zip them off to approximate length all at once with the die grinder.
Good idea! Thanks for watching
How do you not gouge the mold that way?
Thanks for sharing, can you do very small diameter pins with this approach too? Say 1 or 0.75 mm in dia?
Do the pins float in the ejector plate? Thanks for sharing
yes, I usually let them float in the plate, fixes tollerance problems during final build and prolongs ejector pin hole life with lower binding. Thanks!
Cool, thanks
Like the reflective tool Z calibration, does sticking the tongue out help at all? 🤔. I'm fairly new to CNC machines, and use cigarette papers for non marking Z axis calibration, though newspaper is equally effective, but gets a bit soggy with coolant present; I've tried to use feeler stock, but prefer paper method.
If I may suggest when grinding narrow section on a surface grinder, angle the part so that it has contact with the full width of the wheel, then plunge grind.
Great job, plenty scope for shorter pins.
Thanks for sharing. Best regards John.
When I do have to touch off precisely, I often use feeler gauges. Those are normally used to adjust valve play in older cars, and they fit into your pocket easily.
Hi John,
Thanks for the feedback. Yes, thanks for the tip on angling the work in the grinder. I seem to forget that trick ~50% of the time. I also use the copier paper sometime to set the tool, I do try to remove 0.004" paper thickness when do. Thanks for watching!
Nice batching.
Thanks for watching John!