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100 The PCB Magazine • July 2017 cial and industrial applications but causes prob- lems for IMDS reporting. IPC material data that is sufficient for IMDS, like the example in Figure 1a, is probably the exception. Since IPC reporting is voluntary, it is not often done unless it is a specific condi- tion of purchase. If the IPC MCD is absent or incomplete, for any of the following reasons, then creating an MDS report is problematic: • Missing weights • Missing or incorrect CAS numbers • Missing manufacturer name or part numbers • Missing BOM tree hierarchy Research is required to find the missing data. This may involve contacting the original com- ponent manufacturer or supplier, or searching the IMDS database to find exact or similar com- ponents previously entered. This can take con- siderable time and success is not assured. With proper material data quality control at purchas- ing and receiving and during production plan- ning, this situation can be avoided. I recall an extreme case when an engineer who was assigned to get an IMDS number for his company's automotive product declared: On my BOM I have about 80 components (re- sistors, capacitors, LEDs, etc.), some of which have multiple approved vendors. For example, one capacitor could be purchased from six dif- ferent manufacturers. I have no way of knowing which manufacturers were used to produce our circuit board as we have our boards assembled by an outside source. There could be thousands of different combinations of components on the PCB. How do I handle this in IMDS? This engineer's dilemma reveals a level of material data quality that is not ready for IMDS prime time. The problem here is that an IMDS num- ber corresponds to a specific set of manufactur- er's part numbers, chemical compositions and weights; in principle, the substitution of a sin- gle component part number requires the origi- nal IMDS record to be updated unless the chem- ical compositions and weights are nearly iden- tical. Tracking, checking and updating multiple component substitutions on IMDS is a night- mare. One answer is to standardize on BOM of component part numbers specifically approved for the automotive application, and require outside suppliers to verify compliance by pro- viding complete IMDS data on the shipped parts, either in complete IPC format or directly in the IMDS. Component source substitutions can be allowed if the materials data variations are within certain tolerances. Ultimately it is the chemical substances, weights and location in the car that matter, not the manufacturer's brand. These examples demonstrate that electron- ics fabricators who are new to the automotive industry, or whose automotive output is a small part of their total production volume, need to employ best practices in material data quality control. That process should begin with materials specification and purchasing and con- tinue through incoming inspection, production planning and inventory control. With sufficient IMDS data established early in the production process, creating IMDS com- pliance documents will be much easier and shipping delays can be avoided. PCB Derrik Snider is a member of the American Society for Quality Control and a past examiner for the Malcolm Baldrige Award. He is the founder of IMDS Data LLC, which helps compa- nies meet their IMDS requirements. To contact Snider, click here. AUTOMOTIVE SUPPLIERS MUST MANAGE DATA FOR IMDS COMPLIANCE " Tracking, checking and updating multiple component substitutions on IMDS is a nightmare. "