BOM Optimization for Rapid Prototype Manufacturing

The business model, cost structure, and margins for mass manufacturing are totally different from those found in rapid prototyping. The same goes for PCB design and preparing a manufacturing order. Manufacturing a prototype brings along a different set of considerations compared to producing a volume run, and much of this has to do with the fact that the actual designs can be quite different.

BOM optimization for a prototype order has a lot less to do with cost than it does to do with parts availability and expediency. When you're preparing for rapid prototyping, choose your suppliers carefully as a single supplier delay can derail your entire schedule. Make sure to better understand these points before you send in your rapid prototyping order.

How Rapid Prototyping is Different

PCB prototyping is always done at low volume and low mix. You are producing and assembling a one-off run of boards at single digit or double digit quantities. PCB prototyping lead times can vary greatly depending on where you produce. In total, the time required to produce is the sum of your fabrication, assembly, and shipping times, assuming no delays in procurement.

Rapid prototyping is just like it named its name suggests: PCB prototyping, but faster! The business model for rapid prototyping focuses purely on speed, often at the cost of quality. If you throw enough money at your rapid prototyping house, they could get the job done extremely quickly.

If you want to use a rapid prototyping house to build your board, here are some things you can expect.

Rapid prototyping successfully is dependent heavily on scheduling the assembly run correctly. The moment there is a delay in deliveries of any part of your order, you essentially lose all of the time value of rapid prototyping. That translates to additional costs that you cannot recover.

Rapid Prototyping BOMs Are Not About Cost

When you pay for a rapid prototyping service, the main thing you are paying for is faster production time, not necessarily higher quality or more advanced capabilities. The markup on these services is quite large and will typically exceed the cost of components for most rapid prototyping runs. This means when you create the BOM, cost is not usually the factor for which you will optimize.

Take they look at the example cost breakdown shown below. This cost breakdown is for a recent project acquiring reasonably fast turn time of 5 days for fabrication and 10 days for assembly. This was performed at a rapid fabrication house and a separate rapid assembly house, both in the United States. For a run of QTY 10 boards, we have the following costs:

• Fabrication: $1,292
• Assembly: $2,174
• Components: $893
• 2-day shipping: $140

This comes to a grand total of $4,499 for qty 10 boards with 68 unique BOM lines. Volume production, the components are one of the major costs, and they are usually the major cost when advanced components are placed in the board. In rapid prototyping, the opposite is the case, especially when fast turn time is needed.

Your BOM Keeps You on Schedule

Getting through rapid prototyping on-schedule requires selecting the right sources for purchasing your components. When you create a rapid prototyping run, the components have to be ordered from somewhere, assuming you do not hold them in inventory. If you select the right sources for your components, then you have a much higher chance of staying on schedule. Your component sources should probably be the following types of companies:

• A distributor with global presence and that can ship to your home country
• A distributor with very broad inventories and diverse range of parts
• A larger distributor with relationships with freight carriers

If you're located in the United States, is usually means selecting Digi-key, Mouser, Arrow, or Newark. When selecting suppliers

Here we haven't said anything about consolidating BOM lines to try and get volume discounts on parts. In rapid prototyping, BOM line reduction is usually irrelevant and it takes just as much time to complete this task as it would to ensure your components get delivered on time from reliable distributors. Focus on the on-time delivery aspect, and you'll have much less headache when creating an order with your contract assembler.

To help you stay on schedule, your BOM needs to have accurate, up-to-date information on your components and their capabilities. Engineering professions rely on the ActiveBOM tool in Altium Designer^® to ensure BOM data is complete and organized. When you’ve finished your design, and you want to release files to your manufacturer, the Altium 365^™ platform makes it easy to collaborate and share your projects.

We have only scratched the surface of what’s possible with Altium Designer on Altium 365. Start your free trial of Altium Designer + Altium 365 today.