Pop Up Registration Pins

1

Hey Guys,
On a previous machine I had used air cylinders for pop up registration pins but the rod of the air cylinder has a good bit of slop. So for the AVID, I made an aluminum bracket (I used a mill to make these) that could attach to the side of the 8020 for easy positioning and made a top plate with a precision bore that would “guide” the rod. The air cylinders were SDA40x70 that I got off ebay a while ago. Attached is the step file if anyone wants to make their own.

IMG20250218114520
IMG202502181145201920×2560 402 KB

IMG20250221180955
IMG202502211809551920×1440 222 KB

IMG20250226095618
IMG202502260956181920×1440 360 KB

IMG20250226095624
IMG202502260956241920×1440 263 KB

IMG20250226095609
IMG202502260956091920×1440 436 KB

Air Cylinder Bracket SDA40x70.step (131.0 KB)

2

Those are SWEET Paul!

PS what’s the material you used for the plenum? Is that phenolic or something else?

3

Thanks…I was cheap and used Black PVC. I know the PVC will expand/contract a ton with temperature but my shop in the basement is relatively climate controlled and I left a 0.030" gap between the pop up pins and the PVC so that it doesn’t throw off the pin alignment.

4

Thanks for the file. Was going to do the same thing. You saved me a little time. I do appreciate it.

1 Like
5

@paulk would you consider making a few of these brackets for sale?

6

I’m too tied up with other projects to make any more of these but you’re welcome to send the files to a machine shop. It’s also okay with me if there is someone here that wants to use this design and make/sale them.

7

I assume this is for 2 sided machining, something I’m interested in but have never attempted. Recently, a CNC shop that is machining some HDPE for me (until I get up and running with the new Avid), said they cut the parts then do the 2nd side machining per part. Apparently they can’t get reliable positioning. This is a fair sized shop and they have more experience than my admittedly novice levels.
How accurate is 2 sided machining? I understand, theoretically, how it’s done, but if you get the math and positioning, shouldn’t it be near perfect?

8

For non-sheet goods, having a static fixture and routing registration pin holes into the fixture and item routing will give very accurate two-sided machining. For popup pins, it depends on the deflection of the pins. A fixed fence (if you don’t need to cut on the edge) would be a way to ensure a sheet good flip is accurate.

9

Yes, it can be used for 2 sided machining but I more regularly use it so that my G54 work offset is always in the same location and I use the pins for aligning my material so that I don’t have to use the touch plate to locate the work offset. Theoretically you can get 2 sided machining perfect but it’s difficult to get it better than 0.005" - 0.010" on a larger router due to a number of variables (how square is your table, how accurate is the rack, changes in temp/humidity since you cut the first operation, etc)

10

I had a job that required cutting a large number of sheets where the cuts went right up to the edge of the full sheet, so accurate placement of the sheet was critical. The work was held down with a vacuum table, but since the cuts went over the edge of the sheet, any indexing material or fences would get cut up.

Having popup pins that disappear during the actual cut operation, in this case ,would have been very nice. Anything that can cut time on a job is worth the investment, imho.

11

I would expect that, for two sided machining, you’d need a second set of pins on the opposite edge for when you flip the board over? Otherwise you’re relying on the actual dimensions of the sheet goods…