Question: What information is needed for a budgetary quote and when should I request pricing?
Flex and rigid flex are a fast-growing portion of the PCB market. As we are challenged to put increasingly complex electronics into increasingly smaller packaging, flexible constructions are a solution many are starting to explore. The advantages for space, weight, and packaging are well advertised for good reason. But it is not uncommon to be concerned about the cost and due diligence that needs to be done to ensure it makes economic sense to use this product.
I routinely give the advice to work with your fabricator early in the design process to be sure that what you are designing is going to be manufacturable and address any issues related to material availability. Requesting a budgetary quotation early in the process also makes sense to be sure that what you are designing is going to fit into the general budget for the project. In another blog, I will go into more detail about why flex and rigid flex constructions are more expensive than their rigid counterparts, but in today’s blog, I want to look at tips and advice to be sure you are able to get a quick, ballpark price that actually is in the ballpark.
Here are the things that are most critical for budgetary pricing:
A proposed materials stack-up
Whether you have specific material constraints or are flexible with materials, it is a good practice to ask your preferred fabricator for a stack up. This will be a good time to understand if you are using materials that are “common” or “typically in stock” with your fabricator. It is also the time to understand which if any, of the materials in the stack up have a long lead time that will need to be factored into the project timeline. Obviously, common materials will reduce lead time and eliminate any minimum lot charge pricing. However, if long lead time materials are required, once the stack up is firmed up, “pre-ordering” material while the design is being completed can be helpful in reducing the overall lead-time for the project.
What size do you anticipate the part to be?
The price per piece is driven by the number of pieces that can be nested on a production panel. The complexity of the design will often dictate the size of panel that is used. Typical panel sizes are 12” x 18” and 18” x 24” with at least a 1” border all the way around the panel for coupons, tooling holes, etc., effectively reducing the usable space to 10” x 12” or 16” x 22”. Often, flex and rigid flex have an unusual shape and the ability to fit economically within these panel sizes, or creatively nest parts to help improve panel utilization, has a significant impact on cost.
Another factor that impacts price is whether this will be a delivered in a single-up flex, or if it will be delivered in an array. If you do intend to have parts panelized in an array, it is a good idea to include this at the budgetary quote stage. Working with your fabricator, ask for their recommendation for a cost-effective array unless you already have one developed, and if you have developed, be sure that it maximizes the use of space on the larger production panel.
What are the quality requirements?
IPC Class 2, IPC Class 3, MIL-31032, all have different requirements and different price points that are important to capture in your estimates. Will you have a requirement for a 3rd part test? This too has an impact on the total cost.
What are the minimum drilled hole sizes?
The minimum drilled hole size can have an impact on pricing. Mechanically drilled holes are typically less expensive than laser drilled holes and mechanically drilled holes less than .008” can have an impact on cost. The cost added for smaller mechanically drilled holes can be very dependent on the fabricator’s equipment and process, so be sure to understand those capabilities.
What is the via structure?
Do you anticipate the design to be standard thru hole construction? Will there be blind and buried vias? Will there be micro vias? If there are micro vias, will these be filled and stacked or staggered, and how many levels? The number of lamination cycles needed to fabricate the flex or rigid flex has a dramatic effect on cost.
What is the preferred surface finish?
Flex and rigid flex designs can use all the same surface finish options as a rigid board. Do you need HASL? Lead-Free HASL? OSP? Silver? Tin? ENIG? ENEPIG? ENIG? These all have different price points and both pricing and lead-time are impacted by which surface finishes your fabricator has in house and runs most frequently.
To answer the original question:
Requesting pricing early in the design cycle can help determine if the design will fit within the product budget, something especially important when working with flex and rigid flex, where factors such as material utilization and via structure can have a significant impact on cost. Once there is an estimate of materials, layer count, via structure and quality requirements, reach out to your fabricator for a stack up and budgetary quotation. This is an excellent time to start a dialog and ask questions to be sure you are not inadvertently adding unnecessary cost to your design.