Government agencies around the world have been increasing the focus on safety in the composites production environment, and at the height of this is styrene emissions. As a result, composite manufacturers are exploring alternate production methods to meet new standards.  

New production methods need to not only be safe, but also efficient. A proven alternative is closed mold Light Resin Transfer Molding (LRTM)

Top-Hill OY in Halikko, Finland quickly recognized the impending regulations and the benefits of moving to a closed mold technology. Founded in 1981, Top-Hill OY makes designer chairs for Piiroinen Furniture, cabin components for the S-Series tractor manufactured by Valtra Valmet, truck components, parts for electrical motors and parts for the marine sector.

The Problem:

Like most composites manufacturers, Top-Hill OY started out manufacturing their products using open molds. In the early 1990’s, they were awarded a project that required them to make 18 van roofs per day. While they were capable of meeting this quota using open molding, they soon realized that cutting and trimming the parts was time consuming and difficult. They planned to use robotics in the trimming process, but when using open molding they could not make the parts fit the jig — they needed a more precise finished part to use the robotic cutter.

The Solution:

At that time, they were introduced to a new process by one of their materials suppliers. The process was a new closed mold technology called Light Resin Transfer Molding (LRTM). LRTM was showing great results by producing highly precise finished parts.

Top-Hill OY contacted the primary manufacturer of LRTM technology, Plastech T.T., later acquired by MVP, to investigate bringing this new technology to their production. They bought an injection system and the necessary seals and parts and began using this method in their production. With more consistently precise parts coming out of production, they were able to incorporate robotics into their trimming operation.


In the autumn of 2008, MVP distributor for Finland, KG Enterprises, hosted a training course to demonstrate latest updates in LRTM techniques. Jari Mattsson, Development Director for Top-Hill OY, attended the demonstration.  

Mattson said of the training, “Both trainings were very good. I was amazed how many new things I learned at the second training in 2008.” He went on to say, “We changed our way of making the molds in many ways after that, and further improved our production.”

With the new training and information gained in the training course, Mattsson began to conduct a study of production methods at Top-Hill OY to determine what the future of production in their facility might look like. The company’s production volumes have steadily increased over the years, and Mattsson was studying the possibilities of higher production rates using a different production method. His conclusion was that, “with RTM, LRTM, and Multiple Insert Tooling (MIT) LRTM, we can still make more pieces with the same factory space and personnel.”

“Stricter rules in work environment, demands for ventilation, ex-proof electricity systems — all this forces companies to start using closed molds. With closed mold technology you can save in factory requirements and production area costs (i.e. less pressure from building, fire and health safety authorities). Also, if you want to make the production more automatic for trimming and improve the quality, the answer is LRTM,” said Mattsson.