SMT & Hamilton Mold Alignment Woes...

[BrianAtMRP]

Hey all,

Pretty much what the title says. We've got refurbished SMTs and Hamiltons here and lately we are having MAJOR issues with molds coming out of alignment fairly rapidly, to the point that certain presses are having to be re-aligned as regularly as every 8 hours or so.

We use RPA made molds with the "euro-spec" center cut out (slanted inward instead of straight down at the lip,) and have determined that at least some of our issues with off centered pressings are because of fitment between our centers and stampers during loading, but a great deal of it is definitely movement of the molds or bolsters.

I've done a little google fu and allegedly Gotta Groove had NASA (hah!) come in and provide a high-tech solution, but haven't seen specifics, though we have reached out to them.

As far as I'm aware, our hardware to mount the molds is standard, though we have removed the guide posts on most of our SMTs, as wear on them made them wind up working against us. We have a specialty tool that lines the molds up by going through both center cut outs, but we get mixed results with it, so largely we correct alignment by eye. We've tried just loosening one mold vs both, tried leaving the molds snug and doing it by the bolster plate. Nothing so far has given us a dependable long-term fix. We've been running these things 24/5 for about 2 years, thinking entropy could be a major factor but figured I'd reach out to folks whose cumulative experience far outweighs our own.

Any veterans have pro tips or creative solutions they've come up with to consistently line 'em up and keep them in line? The latter is really the crucial part. I have some budget to work with, as at this point the issue is ubiquitous enough that it's coming back on us from clients.

Thanks in advance.

[Aussie0zborn]

Are you saying you removed the four guide posts on the bolsters?

[BrianAtMRP]

I'm referencing the four cylindrical posts about 4" in height that would normally surround the mold coming out of the lower bolster. I believe we're talking about the same thing.

We bought most of our presses from the shop up in Brooklyn that shut down years back, and a couple of our SMTs came from Erika I believe. Some of the SMTs didn't even have all four posts by the time I started here (~5 months after we became operational) and it was decided at a point that the posts were actually pulling us OUT of alignment, or otherwise doing basically nothing due to the wear on the posts themselves as well as the point in the upper bolster that they guide into.

A number of our molds used presently were sourced from GZ, and they sit inside of a retainer ring due to the difference in dimension between the cut-out in the bolster and the footprint of their molds. I wanted to blame all of our problems on those, but we still get issues with traditional RPA supplied molds that don't have to use the rings.

[Aussie0zborn]

In a two-piece mould you have the bolster and the insert (the actual mould).
When the insert is worn or dead, you simply replace it using the same bolster.
If the bolster is worn, the insert will float around in the bolster. So, while the guide posts on the bolster are keeping the top and bottom bolsters centred, this may have no relevance to the mould insert which is not centred in the bolster.

If this is the problem, you can drill and tap four holes in the side of the bolsters and insert set screws.
The set screws allow you to position the insert in the absolute centre.

I can't imagine why you would press without guide posts and think it's a good idea.
Why are the guide posts causing problems? Are your platens parallel?
Do you grease the guide posts daily? Ofcourse they're going to wear and they should be replaceable.

As for the "euro-centre", unless your centre bush is loose and your stamper is slipping, this isn't the cause of your problem.

Have you checked with RPA and Donny?

[BrianAtMRP]

If I remember correctly, Donny and Greg were the ones who suggested removing the guide posts, haha. I may well reach out to RPA and see about buying fresh guide posts, if for no other reason than to check another possibility off the list.

Will look into the platens. One of the SMTs that won't stay lined up is running with basically brand new bolsters, but it's certainly possible that bolster wear is the culprit on some of the other machines.

I like the suggestion of set screws in the bolster. Have you tried this yourself?