Understanding Alternate Sourcing, Part 2

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:

  1. Confirm
  2. 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.

  3. Review
  4. 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.

  5. Explore alternative resources
  6. , 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!

  7. It may be possible to cannibalize
  8. from other products to find the same parts until the newly sourced parts can be identified and delivered.

  9. It is possible to change
  10. , 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.

  11. The board or circuit layout may be able to handle multiple package variations.
  12. 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.

  13. Sometimes the parts may be pulled
  14. 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.

  15. Double check
  16. 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.

8 comments on “Understanding Alternate Sourcing, Part 2

  1. Brian775137
    December 8, 2011

    Douglas' comment about having 2 or more alternates already approved for parts is particularly appropriate within the aerospace community.  There, the parameter controls on parts are usually very tight, and there are not too many suppliers who can meet the requirements.  Usually, this is handled by having the alternate sources already listed on the SCD and Purchasing has a choice of 2 or more supplliers who will be able to provide the tigtly-controlled part.  This reduces the amount of time needed to obtain more parts to meet your requirements. 

    An SCD can be very short, and just specify minimal parameters, or very detailed and tightly control many.  It's all based upon the criticality of the parameters of a part which determines whether or not an SCD is required.

    Sometimes, though, an SCD is written to control who is the approved vendor, and then it is called a Source Control Document (SCD), the acronym is used for both types of controlling documents, s, you need to be aware that there are 2 types of SCDs. 

  2. Barbara Jorgensen
    December 8, 2011

    I'm wondering if most of these steps can be done online. I would imagine they can. It still sounds like it is very time-consuming, but as you point out in the long run, it saves time once the design reaches the manufacturing phase.

  3. _hm
    December 8, 2011

    In most situations chaniging parts from controlled document is very difficult. It has lengthy process of ECO, approvals and it should need recertification for many compliance agencies.

  4. Daniel
    December 9, 2011

    I think in design phase itself we have to tabularize similar kinds of components based on parameters. So it becomes easy to identify the alternate components for replacement. Otherwise, it’s difficult and time consuming process.

  5. dalexander
    December 9, 2011

    _hm, You have raised a significant issue that we need to address in another article. Compliance is becoming an ever increasing concern in order to ship product these days. Up to this point in time it has required additional effort to meet all of the environmental qualifiers like RoHS and Halogen Free, but coming up fast in many countries, in particular the EU member states, are the additional REACH requirements. At the present time, there are 53 SVHC, substances of very high concern, and the list is growing. Because the REACH list is dynamic, every part in an Item Master will have to be under constant scrutiny by the CE and certification documentation will have to be as equally as dynamic. A good CE department will have to allocate additional time and effort to keep up with these environmental mandates. New strategies for part qualification will have to include an equally dynamic means of tracking and updating environmental certification records almost in real time. I strongly recommend that every supply chain professional and engineering support service related position, familiarize themselves with REACH related concerns as soon as possible. is the definitive website hosting the SVHC list, educational material, and legislation. I will also be writing about REACH for Component Engineers. If a company expects to ship product into the EU, Japan, Brazil, India and many others now joining the list for REACH required qualification, then NOW is the time to understand all of the ramifications of REACH and take measures to assure dynamic compliance. As you say _hm, every part will have to be certified as part of the alternate source effort.

  6. dalexander
    December 9, 2011

    Barbara, I think 2,4,5 and 6 requires a physical presence. It helps to have a face-to-face with a Design Engineer as it let's them know you don't think you have all the answers and it reenforces the fact that the DE owns the design. It can be a very valuable time for exchange on other related concerns, respecting the limited opportunities to have uninterrupted meetings with the DE. For cannibalization, you will want to inspect the candidate boards to verify fitness of the part that will be desoldered. Maybe it is a down rev part that cannot be used or was previously disqualified by lot number or date code. Generally speaking, the CE role is a very hands on position as so many things can go wrong if the most stringent attention is required in order to not compound problems.

  7. Anand
    December 26, 2011

    Explore alternative resources, including third-party component brokers or overseas suppliers.

    @Douglas, Thanks for the informative post. How we do make sure if the parts imported from third-party component brokers or overseas suppliers are genuine and not conterfiet ? What precuation we should take while selecting the supplier ?

  8. dalexander
    December 26, 2011

    Anandvy, I have been thinking about this a lot as counterfeit parts are a major problem for everyone including the military. I am thinking about this in the same terms as I think about drug trafficking. The people making and moving the narcotics don't give a rip about the lives they are destroying and it is possibly the most selfish manifestation of human nature and heartlessness around. Part counterfeiters don't care if their parts end up in critical use medical products that may have life and death ramifications. Thankfully, most Manufacturer's final test to eliminate bad product thus reducing and possibly eliminating any field impact of counterfeit parts, but imagine the counterfeit part is the right part but used and re-blacktopped to look new. Now the factory has inadvertently put a low reliability part in a hi-Rel application. The lifetime of the product is shortened and consequently, the product does not work at some point when it is needed desperately. I know EBN is covering counterfeiting in their blogs and it is something on which we all want to stay current. I have several ideas for detecting and preventing counterfeits but I am no expert in this field and suggest we all keep investigating the technology for counter-counterfeiting. If you know of a forum where ideas can be presented, I would be happy to participate. Otherwise, you can email me at and I will share my thoughts with you or others who want to discuss this issue and possibly contribute to the solution and not just to the verbiage.

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