A leading manufacturer of designer windows and doors was experiencing high scrap and rejection rates with its patio door assembly.  The customer’s assembly system first required insulated glass to be inserted into trim.  Next, the door panel was built around the glass and trim.  This assembly process caused glass pieces to break, resulting in high scrap levels and a large number of rejections, as well as safety issues for the assemblers.

Understanding that their design would likely need to be changed, the customer’s management team decided to pursue a flush surround system, which they felt was more aesthetically pleasing than alternative systems.  The flush system would need to be produced from a material that did not expand or contract as much as plastic when the weather or temperature changed (lower coefficient of thermal expansion, or CTE) and could withstand higher temperatures than plastic without distorting (higher heat distortion temperature, or HDT).


Formtech recommended a Wood Plastic Composite material, which had a lower CTE and higher HDT than plastic resins.  This meant that the material could withstand temperature changes and hot environments better than other materials, including PVC.  This material also looked like wood, which was an added benefit since it was part of a wood door assembly.  The part was embossed with a wood grain pattern to enhance that look, and the paintable and stainable nature of the particular composite allowed for the homeowner to customize their door to their own home.

Weather Shield and Formtech worked together to develop a two-piece trim system using the Wood Plastic Composite material.  The two-piece system allowed assemblers to insert the glass as the final step in the door assembly process, resolving the issue of the glass breaking.  As a result, scrap levels and the number of rejections were reduced, while safety issues resulting from broken glass were practically eliminated.  In addition, if the final door was deemed defective, the company no longer had to scrap the glass, which was the most expensive component of the door.  This further reduced scrap levels as well as the cost of replacing the glass panel in defective doors.  Lastly, if necessary, the door could be reglazed in the field, meaning that the door and snap-in could be replaced easily compared with the prior system.


Formtech met the needs of its customer.  With the new two-piece system, the manufacturer reduced its levels of scrap and rejections while improving the assemblers’ safety.  The material met the physical properties, including a lower CTE and higher HDT, of the application, and added value by enhancing the product’s appearance.