Can Form/Met Be Ultrasonically Welded?
Yes, though each application requires that the ultrasonic equipment be optimized. This is typically not a limitation. WaveZero has performed simple experiments demonstrating that ultrasonic welding is possible. A large number of equipment vendors are available to provide solutions for a particular need.
At What Stage In The Process Are The Forms Cut Out Of The Polymer Webs?
Die cutting is accomplished in various manners and order depending upon the particulars of the application. In some cases, part outlines are partially die cut while in the web leaving just a very small (< 1/8 inch) connecting tab. This allows the parts to be held in the web, which makes for efficient handling and placement in our standardized racking systems. After metalization, the small remaining portions of the part that attaches to the web are cut. In that application, metalization is also apparent on all edges except for the small area that is cut after metalization. In other cases, the parts are completely separated from the web prior to metalizing and special clips are used to hold the parts for metalization. If independent shields (top and bottom surfaces not electrically connected via edge metalization) are required, die cutting occurs after metalization. Since the edges are not metalized, this results in two independent shields (both must be grounded however).
Are There Any Concerns With The Edges Of The Polymer Film?
We are not aware of any issues or concerns. The die cutting process has been developed and standardized over many years for other commercial industries and is very robust and "clean."
Is There Any Danger Of Small Metal Particles Being Created From The Die Cutting Process That May Contaminate Or "Short Out" The PCB?
The process order deployed by WaveZero provides for thermoforming and die cutting to be accomplished prior to metalization. Through proper design of tools, inadvertent formation of slivers or small particles on the thermoformed (but not metalized) polymer film is avoided. Quality control inspections prior to metalization also would catch inadvertent problems from die cutting. The subsequent metalization process is done on structural complete and intact parts thus eliminating any contaminating particles. In the event that parts are retained in the web (see Question 23), the subsequent post-metalization die cutting is done over a very small area where the tab is located. Metal particles are minimized and eliminated in post-metalization cleaning and inspection.
What Kinds Of Adhesive Are Used To Attach Form/Met?
Both conductive and nonconductive dispensed adhesives are used for attachment purposes. For instance, if the available space is limited, small access holes are designed into the Form/Met flanges. These holes allow for the application of conductive adhesives that are easily applied during the assembly process by a CEM that is certified by WaveZero. Through proper design, the use of conductive adhesives can be minimized. Other design techniques can be used when a nonconductive adhesives is judged more desirable. WaveZero also can use die cut adhesive tape (such as provided by 3M and others) with have either isotropic or anisotropic ("z-direction") conductive properties.
Have The Adhesives Been Tested For Heat, Humidity, And Conductivity?
All adhesives used and specified by WaveZero have complete specifications and performance documented by the supplier. These adhesives are the same as typically found in modern SMT manufacturing methods and thus, they are designed to withstand the rigors of assembly and post-production use.
How Is The Connection Made From Each Side Of The Shield?
With Form/Met, a number of different attachment mechanisms are possible. With the inner surface metalized, the metal layer connects directly to a guard trace or other grounded connection on the PCB. Adhesives, either conductive or non-conductive, are used to keep the shield in place. When the outer surface is metalized, the shield will contain holes in the flanges that make contact with the guard trace. Conductive adhesives then achieve the contact between the guard trace and the top side metalization.
Where Does The Prototyping And Manufacturing Take Place?
Prototyping and manufacturing occur at our manufacturing facilities located in Elk Grove Village, IL (near Chicago).
What Test Equipment Is Required For Quality Assurance Purposes?
Quality assurance is generated though two simple tests. The first is for adhesion in accordance with ASTM D3359. It requires a crosshatch tool and uses Permacel 99 tape. The second test involves using a surface resistivity meter to assure that the surface properties are within the specification.
Will Wavezero Product Accept Standard Manufacturing Cleaning Processes? Solvents? Water?
Generally, "Yes." A particular cleaning process or operation needs to be verified, of course, but Form/Met is based upon the use of aluminum, a material noted for its ability to withstand environmental stresses.
