Pulls Life Time for a Composite Layup Tool 2

[Cisnerjo1973]

Hello !
I have a question for the experts, is there any amount of layup pulls (usage) for a composite laup tool to start getting weak or to present internal leaks? I heard years ago that usually a fiber glass layup tool can last between 60 up to 100 pulls, but also it depends the temperature and the way people handles the tool. Is there any specific amount of pulls that could say enough parts are built a new tool must be made.

We have a fiber glass tool that its worn out and we are still making sandwich parts over it (two plies of prepreg-honeycomb core- two plies of prepreg), but the top coat surface from the tool has already too many pin holes that are transfered in to the part, besides that on the bag side of the part we locate a press pad (template) since the customer also request a good bag side surface pretty much same as tool side, unfortunately the same results are observed on the bag side even we the template does not has that pin holes situation, I didnt know this issue could also go up to the bag side too is that possible? Basically we are seeing either pin holes but also white spot areas pretty much as delamination where we cant see the honeycomb core due the white spots. The tool is loosing 7"HG in 5 minutes this is an indication of problems during cure cycle. I bagged the tool and placed it under vaccum but with no prepreg or material at all except the bagging materials, placed the tool under 280°F to check if the temperature could increase the leaking I monitored the leak and it only lost 1"HG during the cure cycle, maybe with prepregs it might behaved completely different, unfortunately I cant make them to made a new tool thats why I'm posting this and asking for the expert people support.
Thanks a lot !

 

[ctopher]

Are you asking about the bag or the tool? When I used to work in composites, in production we started doing no more than 2 pulls for each bag because pin holes could appear. Sometimes they lasted longer, but we limited it to 2 so not to waste parts.

Chris, CSWP
SolidWorks '17
ctophers home
SolidWorks Legion

 

[Cisnerjo1973]

Hello ctopher,

I'm asking about the layup tool.

Thanks !

 

[berkshire]

The tool or mold service life, is entirely dependent on the care it received during fabrication, and it's use, and care, during its life. I have seen some tools only produce 15 or 20 parts, and others produce several hundred . There really is no hard and fast rule. Sometimes a tool can be rejuvenated by coating the back and ends, with a layer of epoxy varnish but this is really only a stopgap measure. If the contact surface is bad, then grinding out , applying tooling epoxy and re sanding to profile, is your best bet short of remaking a new tool, this depending on labor costs, it in the long run, may be cheaper to make a new tool.
B.E.

You are judged not by what you know, but by what you can do.

 

[Compositepro]

Northrop-Grumman have had some BMI (bismaleimide) composite tools in production for 20 years and hundreds of cycles. I was told that they sometimes have to refurbish Invar tooling more often than BMI because the operators know that you cannot cut material on a composite tool, but do so on Invar.
Many epoxy formulations are not well suited to long term exposure to high temperature cure cycles. The resin degrades over time and micro-cracks.