Although it is true that every press technology has its place, there is no doubt that the three-chamber membrane press has become the system of choice for high production.
Before buying a membrane press, make sure you understand the distinctions in the systems.
Though some mistakenly refer to them all as “membrane presses,” there are four basic types of 3D laminating systems: bladder (liquid filled) presses, membrane presses, membrane-less presses and vacuum formers. Each technology has its place, but not all do every job equally as well.
The pros and cons of each system have been covered in blogs on WoodworkingNetwork.com. What follows are some basic definitions of each systems, derived from the 3D Laminating Glossary which can be found at FormellaCSI.com/glossary.
Bladder Press: Although this term is often used to describe a membrane press, it is a general belief that it was originally used for liquid-filled membrane presses, developed in the late 1960s and still used today. In this system the membrane is either pressurized via the injection of thermal oil or, in the case of liquid bed presses, through displacement pressure as the press is closed. The thermal oil is heated to provide the heat source. Because liquid pressure is safer to operate than air pressure, much higher pressure capacities are available with this technology.
Membrane Press: This usually refers to a press that incorporates the use of a membrane as well as positive pressure and vacuum. However, some membrane presses eliminate the use of vacuum below the 3DL and merely allow a way of escape for trapped air as pressure is applied.
The membrane draws heat from the heating source, usually a platen, then transfers that heat into the 3DL for softening, forming and adhesive activation. Air pressures of 30 PSI to 60 PSI are typically used for 3D laminates.
Membraneless Press: Usually refers to a press that incorporates the use of positive pressure and vacuum but without the use of membranes. In this system a full sheet of 3DL must be used to create a pressure chamber above the laminate and a vacuum chamber below.
In some cases, presses have been designed to eliminate the vacuum system below the 3DL and merely allow a way of escape for trapped air as pressure is applied. The 3DL draws heat directly from the heat source, usually a platen, and then forms over the substrate and activates the adhesive. Air pressures of 30 PSI to 60 PSI are typically used for 3D laminates.
Vacuum Press: Often referred to as a vacuum former, this system eliminates the use of a pressurized chamber above the 3DL and relies only on vacuum under the overlay to form it to the substrate. The 3DL is heated using either heating lamps or infrared systems. Some vacuum presses offer the option of operating with a membrane for greater security and flexibility.
A bloggist for WoodworkingNetwork, Bill Formella has nearly 20 years of experience in the 3D laminating industry with extensive involvement in every facet including machinery, materials, supplies, as well as training and technical support. He is the Product Applications Specialist for Smartech Intl, providing sales and technical support for the company’s membranes and other press-related products. Bill also is president of Formella Contour Solutions and is the owner and moderator of the LinkedIn group Membrane Pressing & 3D Laminating Design. You can reach Bill at email@example.com and follow him via twitter @formellacsi.
Have something to say? Share your thoughts with us in the comments below.