Some Causes for Premature Tie Bar Failure…

Keep in mind that clamp maintenance should be routine and comprehensive. Once a tie bar breaks, it is critical that you ensure everything is level, parallel, lubricated, and functioning properly. If you are unsure, have an expert come in to perform a detailed analysis of your tie bars, platen movement, lubrication, bushings, and leveling.
What are the various causes of a broken Tie-Bar on a Toggle-Type Injection Molding Machine?

My Response:
The tie bars are designed to last a long time, but only if ALL the following conditions are met:
All the tie bars are parallel
The mold travels perpendicular to the platen surface
All the tie bars are properly level
The machine is properly leveled and supported
The force is applied evenly across all tie bars
The mold is properly sized and centered
The tonnage requirements are centered (balanced)
The platens and tie bars do not get too hot
Proper lubrication is applied
Below are many of the factors that cause premature tie bar failure 
Ex-centric (off-center) mold
Mold with an off-center tonnage requirement
Machine not level or properly supported
Too much unsupported weight on the movable side 
Travel is not perpendicular to platen surface
Platens not parallel
Hot runner molds without insulator plate
Over-clamping a mold
Uneven mold wear
Bent or twisted machine base 
Mold too small for the machine
Poor initial construction
Poor or uneven lubrication
Excessive platen concavity
Cracked platen
Uneven mold bolting
Excessive platen stoning
  1. SUNNY left a comment on 2016/07/26 at 12:31 am

    Hello ,
    If the failure occurs in one of four tiebar within operation of one avoid this
    For the maintenance of tie bar in injection molding machine ,is it required for maintenance by ultrasonic examination?
    Please reply as fast as possible.
    Thank you

  2. Andy Routsis left a comment on 2016/07/26 at 9:28 am

    It is good to inspect the tiebar stretch with ultrasonic inspection at least once a year. You should also benchmark the stretch of each tiebar with outside micrometers so you can make a quick inspection if problems arise.

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