Post Mold Operation Tooling Fixtures
EPW custom build’s a variety of post operative tooling fixtures to complement the molds we manufacture. Post operative tooling fixture creation gives our customers “one stop shopping”.
Complete mold and fixture purchases allow for single source accountability and continuity between the mold and fixture surfaces relative to parting line and run off consistency.
This capability ensures our customers consistent part quality while allowing EPW to implement project management to oversee the entire project having both the mold and post operative fixture designed and manufactured at one location thus saving customer time and resources.
There are several types of post operative fixtures that are key to a successful part manufacturing system ranging from water jet trim fixtures, checking fixtures, assembly and cooling fixtures. Each of these mold fixtures are unique and custom built concurrently with the molds manufactured at EPW. Each fixture adds both quality and added value to the end customer product being manufactured. Below a brief summary of fixture types and how they are typically used.
Water Jet Trim Fixtures:
Water Jet Trim fixtures are used primarily for trimming “soft trim interior parts” such as carpet product, headliners, trunk liners, rear package trays but can also be built to trim plastic parts as well. Many times the actual water jet trim surface can be laminated from a master model or REN / wood check fixture surface.
EPW laminates the fixture from polyester resins or epoxy resin systems dependent on fixture size and EAU of parts needed. In some instances where a high volume of parts are going to be trimmed or if the service life exceeds 4-5 years as typical in automotive, EPW will CNC machine a aluminum fixture surface. Aluminum fixtures are more durable and last longer than the epoxy or polyester fixtures.
Each fixture type EPW creates has stainless steel guards or shrouds that protect the integrity of the fixture from the powerful water jet stream that is intensified to trim interior holes and the perimeter of the product.
EPW has a solid engineering approach to operator ease of use, how the off fall is removed from the molded part and has several unique mounting approaches of how the actual water jet trim fixture is located to our customers trimming cell. Overall when volumes don’t warrant a hard trim die or they are cost prohibitive a laminated epoxy, polyester or aluminum water jet trim fixture can be a much more cost effective alternative.
Checking fixtures are a key facet to overall product quality and can be constructed in several different styles and types. Many of the urethane products or “soft foam” products require Lexan blades that check the overall tolerance of the parts.
Lexan is a material that is possible to look through, so the product can be visually inspected on 100 mm grid lines on several sections at once. Typical “soft foam” product check fixtures that EPW often builds are for headrests, and seating foam.
Other checking fixture types may be for back foamed components which have an “A” surface barrier or skin. The “A” surface barrier / skin is then backed with urethane to provide fit to the automotive sheet metal surface and provide sound deadening properties as well.
These types of back foamed products often have a CNC machined REN (man made wood material) cut to the back side of product. This allows the operator of the fixture to identify and check all interior trimmed out holes in the part and the part perimeter tolerance.
The checking fixtures manufactured by EPW always have 100 mm grid lines, interior trim outs and perimeter trim tolerance bands scribed directly on the fixture for ease of use. Tooling balls are also installed to allow for quick set ups in the event of future engineering changes.
Assembly Fixtures:There are many different types of assembly fixtures as they range in complexity of the operation being preformed. These fixtures can be manufactured from aluminum, REN or epoxy laminated materials dependent on the application. They can also be automated or a manual operation. A typical assembly fixture may simply add a post glued component or sub-assembly onto the molded product to allow for a higher quality product and could also take complexity out of the molding tool.
EPW currently manufactures these assembly fixtures for many soft trim components such as door panel assemblies, automotive carpet and other soft trim products. While manufacturing the molds concurrently with the assembly fixture, it insures that the entire run off beyond the mold parting line is exactly the same as the fixture. This allows proper fit and continuity between the mold and assembly fixture.
Cooling fixtures can be a significant value add to the overall molded product by eliminating part distortion and enhancing overall part dimensional accuracy by keeping key areas on the part supported post mold. Many times once a RIM part, vacuum form part or structural foam part is molded it has a “cure” time for a few minutes after molding. If the part is not properly supported it can increase scrap rates and rework required to insure dimensionally accurate parts.
Cooling fixtures can be as simply constructed as a REN machined “buck” or surface to nest the part post mold or can be constructed from aluminum dependent on product volume. Some of the prior cooling fixture builds also incorporated water lines which allow circulation of cool water through the fixture to accelerate the cooling process while the part is being held into proper position.