Producing open molded fiberglass spray-up parts with precision accuracy

There are many different methods a company can utilize to mold a fiberglass part. Some of these include but are not limited to: hand layup, spray-up, closed cavity bag molding, RTM, RTM lite, compression molding and cold molding. Each process has its own set of unique advantages and disadvantages. Please click the following link to learn about the differences in the various fiberglass molding processes.

When it comes to producing large, durable fiberglass parts with one finished surface, Open Molded Fiberglass Parts—specifically those made using the spray-up method—are among the most affordable and effective solutions available today.
Click here for examples of large open molded fiberglass parts Arrowhead has produced. Spray-up molding offers the ability to create large fiberglass components using simple and relatively low-cost tooling. The size of the part is generally only limited by the production area available.

In the open molded spray-up process, chopped fiberglass strand and catalyzed resin are simultaneously applied to a prepped mold surface using a chopper gun. The operator controls the mixture and distributes it evenly over the mold surface. The chopped glass exits the nozzle, is mixed with resin, and deposited in a consistent pattern. The operator uses rolling tools to flatten the material and remove air bubbles. Thickness is monitored during the build-up process using a depth gauge to ensure proper laminate thickness before the part is left to cure.

Part weight is an important quality factor for Open Molded Fiberglass Parts. If the part is too light, it may lack sufficient strength or durability. If it is too heavy, it could lead to issues with fit, added shipping costs, unnecessary stress on mating components, and reduced fuel efficiency in mobile applications. Precise weight control is essential to achieving consistent, production-quality results.

Arrowhead produces many large open molded fiberglass parts using the spray-up process and has invested in specialized technology to ensure consistency in part weight and thickness. Our fiberglass chopper guns are monitored in real-time, giving operators precise feedback on the amount of resin, catalyst, and fiberglass being deposited. This allows us to deliver parts that meet our customer’s specifications for weight and laminate thickness every time—far beyond what is achievable with periodic manual measurements alone.

Of course, Open Molded Fiberglass Parts still require finishing steps before they can be delivered. Trimming, drilling, finishing, and inspection must all be carefully controlled. Arrowhead utilizes advanced systems at our fiberglass facility to ensure every stage of production is monitored and quality-controlled. Utilizing CNCs, a FARO arm, and Renishaw head, along with detailed process sheets, we ensure each customer’s part is built to spec from start to finish.

Do you have a large fiberglass part that is a candidate for spray-up but requires precise quality control? Give me a call and let’s talk about how Arrowhead can help with your next Open Molded Fiberglass Part.