A good friend of mine just asked the following question…
Is there an industry standard for how much torque a set up person will use to clamp a mold? I know there are specs for the bolt used but I think they’re too high. We use multiple clamps and multiple bolts per mold so the load is distributed all around. Our smallest machine is 55 tons and our biggest one is 500 tons. If you know of any standard, please let me know. Thanks in advance.
For your molds, we typically recommend around 50-60 ft-lbs… If the diameter of the platen bolts is larger on your biggest machines, you may be able to go a little higher. The two main factors would be the weight of the mold, and the condition of the platen… many industry people would recommend generic values around 80-120 but they usually assume ideal situations.
Keep in mind, the clamp functions by stretching a bolt to apply a bending force to the clamp which is held back by the platen threads. As a result, the more torque you use, the quicker one of these will fail (this failure is almost always found in the platen threads). This why we recommend a conservative torque value with additional clamps used when necessary.
It is always a good idea to have a specific torque value to be used at your facility. Much time can be lost when a platen bolt hole becomes stripped and needs repair.