First off, the word cheap is meant to relate to price – not perception of quality! Envision takes great pride in our fabrication processes and our QMS as a whole. No worries there! Moving on….
Envision Plastics uses the NMR Fabrication Technology to produce custom plastic enclosures. While all products we make represent great value to their users (since they do not have to pay for mold tooling), there are ways to keep the piece part price in check as well.
If you have the luxury to design your own PCB board, placing the components that require access through the box on the same edge side of the board is key to controlling cost. This way, it makes it easier to use a two piece design concept we refer to as our UU Enclosure. If this cannot be done, components placed on opposite sides of the PCB are the next best option. Placing components on adjacent sides to each other can really hinder design flexibility and lead to increase cost due to plastic enclosure construction and assembly. All that being said, if components sit behind the PCB edge and do NOT protrude through (or into) the material wall of the housing, the component placement is arbitrary.
Grades of material can certainly affect cost as well. While all of our stocked materials are RoHS compliant, they do not all have the same properties such as flammability ratings, UV protection, etc. Our most economical material grade that is RoHS compliant is UL94-HB rated HIPS (high impact polystyrene). We stock HIPS in thicknesses of 3mm, 4mm, 6mm, and 10mm.
Due to the variability in the demand of select colors, Envision chooses to only stock a few standard colors. The most available in terms of UL grades and thickness options are black PC/ABS (UL94-V0) and HIPS (UL94-HB). We can certainly offer a gray or two, but we are limited on what it stocked for thicknesses. Please note that Envision CAN get custom colors as well, but they are special orders from our suppliers.
Bosses and standoffs are certainly a necessity to mount enclosure internal components. However, in some cases they can be avoided – presenting a nice cost savings. This is especially true if you have the liberty to design your own board or if the components on the PCB allow enough clearance to slide into side wall grooves or even snap into side wall grooves. These side wall grooves require about .060 of PCB edge clearance with respect to the edge components.
Adding branding or cutout labels through means of digital CMYK color printing can be a cost savings over silk-screening or even adding a label. Piece part printing cost is determined by a variety of factors, but there is less setup involved in digital printing than silk-screening.
Every project our clients have is different. Necessary aesthetics, functionality, and regulatory compliance are just a few factors that drive design. While the above cost avoidance ideas cannot relate to every project, it is food for thought as to ways Envision can save you money on your custom plastic enclosure project application.