Methods for measuring Platen Parallelism

[chrisprocess]

In regards to Preventative Maintenance -

1) What is the recommended platen parallelism you guys use? Generally I'd try to see something less than 0.005" - thoughts?

2) What instrument do you use to measure it, and to what resolution? 0.XX, 0.XXX, or 0.XXXX etc.

I've heard there are laser systems that can measure parallelism.
Anyone heard of this? or know who makes them?


Thanks in advance

Chris

[tbramel]

We have looked into Hamer Laser Systems since we have over 260 machines to do annual PM's on. The system is easy to set-up and use. You can check level, check parallelism and platen flatness with the system. The system is not cheap though.

We currently follow EUROMAP 9 procedures for checking parallelism.


http://www.hamarlaser.com/index.php/app/plastics-processing.html

[MTUHusky]

I have never checked the parallelism myself but the method I was taught was to take 3 machinist levels and place the first across the bottom two tie bars next to the stationary half. Then place one level across the bottom tie bars in the back near the screw motor and then place the final machinist level across the top tie bars in between the first two levels. Then take a 50 lb torque wrench and loosen your leveling feet, get everything square and parallel and tighten the feet back down all to the same torque.

I have never seen the laser level method but I will ask my maintenance guys and see what they say.

[brentb]

Some use a parallel (known square) block) solid steel block about mold size for size press. It has clamping flange and locating ring on front side only.
Clamp it in, clamp up on it and use dial indicators,to check clamp parallelism. This is especially important on toggle presses!
KOM

brent

[tbramel]

Some time ago I had presented the same question to Andy Routsis on his Blog site. Here is his response. This is the method we currently use until we get a Laser System.

[chrisprocess]

Thanks all for the helpful information. Will need to look into a laser system at some point..
Currently use a heavy magnet and dial indicator to touch off each corner for a general idea on how the moving platen is positioned.
EUROMAP 9 is a great way to standardize and so is the Andy Routis method. thanks for the info

In recent case the platen was flush when fully opened, but would become warped during mold closing.. The tie bars were fine so it indicated the machine structure was 'drooping' during mold closing because the machine's structure was only on the machine ends (not in the middle). But it's an older machine... Instead of replacing (what seemed like the machine structure) we shimmed the mold to compensate for the downward "droop" (about 0.010")... Probably not the best solution but the machine is married to the mold and it's been running fine since.. Difficult justification to spend more $ on an older machine, really just need to phase it out..

I can certainly see the benefit of a laser system that would detect flatness/ parallelism/ and even rotational movement in the platen during the opening/closing profile and high pressure clamp