When searching for an alternate part, there are basic requirements, procedures, and creative efforts that will provide timely and effective responses for identifying the appropriate replacement component needed for line-down factory emergencies. I discussed the fundamentals of the process in Understanding Alternate Sourcing, Part 1.
Here's a checklist of steps I recommend for guaranteeing a smooth process:
- Confirm the original part is sole-sourced by double-checking the Item Master. It seems like a redundant effort, but many times human error is involved, particularly in panic situations when people overlook the obvious.
- Review the datasheet or specification, and meet with the design engineer to determine which of the part's characteristics are critical and which are not essential for the design under consideration. More than once, I have had engineers tell me the part is really not that necessary in the circuit and it can be bypassed or removed. Many times I have been able to resolve line-down situations by agreeing with the engineer that the tolerance specification need not be as tight as was first specified or by using a part with a higher electrical or environmental capacity. In doing so, I have sourced alternative parts that are lower cost and readily available. For example, a 16V aluminum electrolytic, low ESR capacitor may be substituted with a 25V part, given the same package size and key specifications.
- Explore alternative resources, including third-party component brokers or overseas suppliers. I have called other companies that might use the same part and asked for emergency supplies from their inventories. Don't overlook the manufacturer's representative, who may have the parts in his or her desk. It happens!
- It may be possible to cannibalize from other products to find the same parts until the newly sourced parts can be identified and delivered.
- It is possible to change, in some cases, another component in the circuit in order to specify an alternate part that is complimentary with the end result of the newly paired combination while producing the same overall circuit results.
- The board or circuit layout may be able to handle multiple package variations. Perhaps a capacitor at 16V can be replaced with a 25V part if the new, sometimes larger diameter part does not interfere with the surrounding components.
- Sometimes the parts may be pulled for other kits that are not so critical. The "on hand" inventory may show zero stock, and the parts bin may be empty, but staged for production may be a kit with more than enough parts to keep the line going. Be sure to check all work-in-process. If the kit is being driven by a sales order, the parts may not be released for the production order in crisis. This possibility should be brought to the attention of the materials planner. The planner will check the criticality of the sales order requirement schedule. Perhaps the customer order is due for shipment long after the critical parts will be available again.
- Double check with purchasing to see if there are any open orders that can be expedited.
If items 1-8 do not provide the remedy needed, then the components engineer must initiate an alternate part search as quickly as possible. The original datasheets edited with the design engineer's concessions will help broaden the possibilities for suitable replacement parts. Remember to initiate the CER form and work closely with purchasing and the materials people, keeping them up-to-date with your research on a daily basis. If you don't keep them in the loop, they will look for you several times a day.
If you are performing an alternate part study based upon your own proactive review of the Item Master list, you may approach this effort in a non-harried fashion and select several alternates and, by doing so, reduce the likelihood of another factory line-down incident due to unavailable parts.
There is one last note about alternate sourcing. As much as possible, identify "families" of parts within each class code. For instance, surface mount resistors have literally thousands of values, but they are all made with the same process by a particular manufacturer. A 4.7K and a 5.1K may not be substitutes for one another, but by qualifying a second manufacturer's resistor manufacturing process, then the same values from both manufacturers can be substituted for each other without an extensive qualification process. For example, if a company has been using a 4.7K resistor from one manufacturer and now the designer wants to add a 5.1K not yet on the Item Master, it would be a simple matter of adding the 5.1K to the Approved Vendor List because the entire family had been prequalified.
In the same manner, if multiple resistor manufacturing companies and their respective manufacturing processes have been qualified, then any part from all the companies could be used. Examine your Item Master list to see what manufacturing processes can be identified as common among multiple manufacturers. You will fill in much of your alternate source database quickly. Think about pin headers, D-Sub connectors, MLC capacitors, etc.
Head off the emergency, and this will significantly reduce your daily stress level.