What’s the difference between epoxy resin and UPR(unsaturated polyester resin)? Can epoxy resin to be used for a SMC(fiberglass compression molding ) tool?

What’s the difference between epoxy resin and UPR(unsaturated polyester resin)? Can epoxy resin to be used for a SMC(fiberglass compression molding ) tool?

As a supplier for customized fiberglass products, Shanghai Olimy has been producing and delivering fiberglass products for over 10 years, most of our products are shipped to America, Canada, Italy, France and UK etc. 

We are always asked by customers about the difference between epoxy resin and URP(Unsaturated polyester resin). Generally, epoxy resin is commonly used for hand laid process, while UPR(Unsaturated polyester resin) is more often used for SMC(fiberglass compression molding) process, this is because most SMC(fiberglass compression molding) material is made with normal working temperature, while epoxy resin is with much higher viscidity than normal unsaturated polyester resin, so need to increase the working temperature to reduce the viscidity of the epoxy resin first, only with this way can epoxy resin to be used for SMC(fiberglass compression molding) material. In addition, after forming, you have to increase the viscidity of the material, with both of the above steps, the final SMC(fiberglass compression molding) material with epoxy resin can be used for normal SMC(fiberglass compression molding)  tool and run normal compression molding process.

Abnormal Problems from Plastic Injection Molding-Crack

 During the plastic plastic injection molding process, some abnormal problems will easily happen, such as cracks, corrugations on the surface,decreasing of brittleness, difficult demolding, unstabledimensions,peeling&layered, welding line, Insufficient injection, etc..These problems will affect the specific use of the mold, so we need to find the relevant factors and solutions.

Crack:

1.Mold is too cold.----adjust the mold temperature.
2.Cooling time is too long.---- reducing cooling time.

3.Plastic and metal inserts shrink differently.----preheat the metal inserts.

4.The ejector device is unbalanced in inclination, the ejection cross-sectional area is small or improperly distributed.----adjust the ejector device or retionalise the quantity of ejector pins and their positions. 

5.The production of the slope is not enough, and difficult the demoulding.----correctly design the draft angle.

Next time we will talk about corrugations on the surface.

What’s the difference between fiberglass parts made from SMC(fiberglass compression molding) and hand lay up

What’s the difference between fiberglass parts made from SMC(fiberglass compression molding) process and fiberglass hand lay up process? 

As we all know, hand laid is a very traditional process to produce fiberglass parts, but normally one mold can only produce one piece, the efficiency is very low, also with the increasing labor cost, unit price from hand laid is becoming higher and higher. Another process just comes and solve this 

problem, it’s called SMC process, also called as sheet molding compound or fiberglass compression molding, it’s similar a little as injection molding 

and mainly finished by machines, this means much higher efficiency than hand laid, also as less labor is required, the unit price is much lower than 

hand laid.

So what’s the difference between parts made from SMC(fiberglass compression molding) and parts made by hand laid? Will the Physical performance 

aged after years? What’s the mold life of normal parts made by SMC(fiberglass compression molding) process?

First of all, parts made from SMC(fiberglass compression molding) process will be with smooth surface on both sides, this is the most obvious advantage

 compared to parts made by hand laid.

Secondly, if same thickness, physical performance from SMC(fiberglass compression molding) process will be better than parts made by hand laid.

Finally, same as parts made by hand laid, parts made by SMC(fiberglass compression molding) will also occur aging with years’ strong sunshine or other

kinds of illumination, the life time depends on the working condition, normally it can keep for 10 years.