Guide to Kitting Electronics for Assembly

When you run a design firm or you work as a freelancer, it’s common to find yourself in a situation where you are managing prototype production for a client. When this is the case, you will have an important job to do: consigning components and kitting components for assembly. Some assembly houses will provide procurement services, but typically at a huge markup on the component cost.

This always eats into the bottom line, and while kitting and ordering are time-consuming, you’ll get positive ROI for your efforts as long as you manage the process correctly. This article runs over some simple processes you can implement when kitting components, hopefully you’ll minimize your kitting and ordering time while also preventing delays for your assembler.

How to Kit Electronics

Kitting electronics involves gathering up the parts required for an assembly run and packaging them for shipping to an assembly house. Parts kits should be clearly labeled with an order number/part number, and parts in a kit should be separated into different packaging with clear identification.

If you order parts from distributors, the distributor will kit parts for you and they can send the parts directly to your assembly house. In other cases, where you hold the parts until a prototyping run, you will need to package and ship the parts yourself. Follow the guidelines below:

• If you’re holding parts on behalf of a client, kit up only the parts required for the production run; not all assemblers will hold and track your inventory.
• Make sure you account for attrition; this will typically be 10% to 20% additional parts, depending on the part type.
• If some components are very expensive, inquire about special attrition requirements for your parts.
• Make sure each unique part number is placed in its own packaging and is clearly labeled. Gather up those packaged parts into a larger bag and place in a box.
• Try to minimize the number of packages sent to the assembler. More packages leaves more room for error.

Use Proper Packing Materials

For any of the components you hold and later ship to the assembler, you should make sure to package them correctly. Typically this requires placement of discrete semiconductors and integrated circuits into antistatic packaging, while other components can be packaged in plastic bags. Some components will require vacuum sealing and desiccant, or moisture-resistant packaging, to prevent exposure to humidity. The following materials are used to pack and ship most components and finished assemblies:

• ESD-sensitive bags
• Silica desiccant pouches
• Antistatic bubble wrap
• ESD warning stickers

These same materials can be used for long-term storage of any extra components. When in doubt, take a look at the packaging used by the distributor or manufacturer, and use similar packaging to store and ship components.

Includes silica desiccant pouches with moisture-sensitive components.

Order the Most Important Parts Early

Given the continuous supply chain challenges companies have to deal with, it’s a good idea to identify the riskiest parts early in the design process and order these early. Identifying a risky part is its own skill, but generally these are parts that create the majority of functions in a device, and they have few or no replacements. If these are identified and ordered early, they can be consigned to the assembler as soon as you create your production order.

Send Tracking Numbers to the Assembler

One of the simplest things you can do to prevent a delay in assembly is to send tracking numbers for consigned kits to the assembly house. Assemblers will typically use a BOM as a checklist for shipped parts, but sometimes they can miss something coming into their facility. If they have the tracking numbers in their systems, they can track when your consigned packages arrive at the facility and they can more quickly get parts checked off the BOM.

Should Parts Substitutes Be Mixed?

Sometimes, you will want to send substitute parts that match one of the placements in your BOM. This typically happens when the desired part has insufficient stock, so additional parts will need to be a suitable substitute.

Assemblers will have different policies on substitute parts. Generally, these will need to be in their own packaging and they should not be mixed with the main placement. If you are building a kit yourself, you can always write:

Substitute for PN: XXXXXXXX

on the packaging for the substitute part. This can help prevent any confusion for the assembly house and it allows quick identification for a line in the BOM.

When you’re ready to export your assembly data and a bill of materials for your parts, use the industry’s best CAD tools in OrCAD from Cadence to create your PCB design and layout. OrCAD is the industry’s best PCB design and analysis software with utilities covering schematic capture, PCB layout and routing, and manufacturing. OrCAD users can access a complete set of schematic capture features, mixed-signal simulations in PSpice, and powerful CAD features, and much more.

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