Ellwood & Custom Etch Offer Mold Texture Solutions.

Ellwood Specialty Steel Co. based in New Castle, PA is one of the largest suppliers of mold steels to the plastic mold building industry in North America.  With the growth of plastic parts in these products there has been a significant increase in the application of textured surfaces to the finish of the molded parts.  Texture designs have progressed from simple leather-like or random deep surface patterns to today’s very shallow stipple or geometric shapes that are much more intricate and delicate surfaces.

Traditionally mold textures have been applied by acid etching the desired pattern into the steel surfaces after protecting the adjacent mold areas from the chemical exposure. This process must be carefully crafted and requires much skill and preparation to achieve the desired result.

One issue that can arise using the acid process is the occasional appearance of what are known as “streaks” in the textured steel surface.  These single or multiple areas appear as lighter or darker lines in the desired pattern.  The objection to these streaks is that they transfer to the surface of the molded plastic parts.  Steel suppliers have traced the appearance of texture streaks to the occurrence of elemental segregation within the steel blocks used for the mold construction.  Segregation is a when certain elements in the steel separate during solidification and form locations that react differently to the application of the acid during texturing.  Segregation is present to some degree in all steels and is a natural phenomenon.

But acid texture streaks from the steel mold are unacceptable on plastic parts!  How can this issue be avoided?

Ellwood has formed a working relationship with Custom Etch Inc. also located in New Castle, PA. Custom Etch is the largest laser texturing service provider in North America and has been committed to the laser texturing process since 2010.  Using lasers, infinite surface texture patterns can be created that are forgiving to steel conditions such as elemental segregation.  The laser process ablates the steel surface and can follow all the shapes and contours of a mold core or cavity.  In addition, the need for complete mold tear down and prep of the non-texture surfaces is eliminated.

To illustrate an example, Custom Etch was contacted by a Canadian mold shop that was faced with a large mold cavity that was nearing the required completion date but had experienced acid texture streaks on the molding surface.  Custom Etch was able to remove then re-texture the surface using laser and enable the mold to produce acceptable parts for the end customer.  See the attached photos.

The laser texture process is gaining in preference by molding industry customers. Custom Etch has invested in multiple laser machines that are capable of accommodating the largest molds being built.Concurrently Ellwood Specialty Steel is convinced that laser texturing is a thoroughly reliable method to avoid the problem of segregation streaks.Ellwood has a warranty for our P20 alloys. The warranty has recently been revised to include a statement that our steel will be warranted for the use of laser texturing to not reveal an unacceptable condition for the product application.