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Greetings!
Hallo!
Happy October! I trust all are enjoying the time and things are picking up for everyone!
Seems the weather has turned with first fair amount of rain here in the Northwest, which is not all that bad, though listening to the traffic report this morning it was bad. Anyway a great day to catch up on some reports and get out the newsletter.
The topic is still the clamp area, with some things to watch out for, such as the heavy mold mounted in the small platen. I still remember the stack mold I helped design years ago for 2 @ 10 pound parts and the saddle that was constructed to support the center section. The only consideration was whether the frame of the machine could handle the load which it could per the manufacture.
Keep learning to allow you to stay ahead with knowledge and skills as that makes things competitive. Keep us in mind for your training, and opportunities within the plant.
Ta
Steven
silveysplastics@hotmail.com |
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The clamp bits and pieces |
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The following are some notes or tips / things that the author has encounter over the years in regards to the clamp and in particular the platens of the machines. There is no particular order...
- Weight attached to rear (moveable) platen. In some cases too much weight is added to this platen which causes issue with load on ways, tie bars and alignment when closing. It should be noted that most machine manufactures have a recommended maximum loading (weight) for the moveable platen. This should not be exceeded.
- Has there ever been a noise when closing the mold as leader pins locate the mold half's?
- Have you noticed that when greasing leader pins that one side or top or bottom has no grease on them or is shinny (see #2)
- Do your parts tend to have scuff marks that are always in same spot?
- Uneven wear on tie bars. This is best noticed by examining the tie bars and watching for wear marks. The easiest way to inspect is to place a thin film of grease on tie bars and then after a few opens and closes inspecting to see if the film is uniform around the tie bars. In many cases one will notice that certain areas are shiny, and or no grease.
- Are the platen faces clean? Is there a buildup of rust, condensation or is the witness mark of the previous tool visible? The results in part production could be flash, galling in tool and or a clicking sound when the mold opens or closes. In many plants the faces of the platen as well as the face of the top clamp plates show build-up and rust. In an ideal plant the platen and top clamp plates should be smooth and clean, as these are the surfaces that are to promote the parallelism for the mold and clamp. Should there be build-up and or contaminates on the surface than the resulting force applied and parting line of the mold may suffer the results.
- Having to add shims to mold to correct parting line flash
- Leader pins rubbing and galling
- Similar result to #1 above but due to non-parallelism of mold parting lines.
- No insulator plates, resulting in heating up of the platens. This is best explained as thermal expansion, but the stationary platen is bolted to the machine thus limited in what directions it can expand, while the moveable platen is free to expand in all directions. One should be able to place ones' hand on a platen and hold it there, if in fact it is too warm to let ones hand be there, than thermal expansion may be excessive, resulting in undue wear to the clamp system and also:
- Results again are leader pin knock
- Scuffing of parts
- Parting line mismatch
- Non-centered / off set molds placed in machine without dummy block / support. In certain cases a mold has an offset sprue bushing so that when placing the mold into the press it is not centered in the platen area. If the offset is there than when applying clamp force the platen may distort or rotate causing wear to tie bar bushings and clamping mechanism. This is best corrected by using a dummy block or spacer on the other side of the platen so when force is applied it is distributed evenly between the two platens via the mold and spacer/ dummy block, providing a balanced area of force applied and resisted.
- Not maintaining the lubrication to the clamp mechanisms of the machine.
The above are some of the more common issues in plants involving molds and platens. It is important to remember that the mold is the factory, and was hopefully created to a good design standard so that it is square, and true. The platen / clamp area than has to square and true so as to apply uniform pressure to the mold and thus the parting line. One than must remember that the injection force is trying to open the mold and well if the force of clamp is not great enough, or not uniform. Inspecting for wear, listening to the mold function and checking that all points are lubricated are critical to good functioning clamp and longevity of the press clamp area.
SL Silvey
silveysplastics@hotmail.com
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 need Balance, need repeatability, want a quicker setup and higher yields.... give us a call, we can run a 5-step process over the phone to evaluate what is going on... Lets become productive... Call: Steve 360-882-3183 |
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The following are some of the services that can be provided.
1- Troubleshooting: assisting in the processing
a. At your plant,
b. Over the phone, internet, Skype, MS Messenger
2- Plant Audits,
3- Training / education programs.
4- Mold optimizations / new mold trials
5- Other services
a. program management
b. material development ( oversee with external assistance)
c. testing of materials (oversee with external sources)
d. BTI MeltFlipperŽ ( distributor for)
e. Expert witness
MeltFlipperŽ, is the registered trade mark of the Beaumont Technologies, Inc
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