During our Spring Momentum, we covered one of the most requested topics on ‘Rework vs Scrap and Bonus’, and the best practices to use them. Below are a few highlights from this webcast that you may find helpful.
A rework is a type of production order that allows you to move inventory through a test step again, or even to rework material into a parallel process flow. It is most commonly used in cases of retesting or rescreening finished goods.
Some of the common rework scenarios that you may encounter in your own workflow are:
- Failed parts being retested to be sold as a different part.
- Failed tests being reprogrammed or rebuilt into another product.
- Low test yields occurring on product.
A common question we get asked from our customers is how to return inventory to finished goods inventory that was previously shipped to a customer? In this case, the inventory can be received in a quarantine state, and then pulled into a rework order to retest and repack the goods prior to returning them to inventory.
One common scenario to mention for rework is the option to combine it with reclaim. Previously yielded out inventory (yield loss) can be reclaimed and then allocated to a rework order to see if additional good product can be saved.
Scrap and Bonus
A simple textbook definition of scrapping is discarding of materials. This can occur if material fails or may happen as a result of additional engineering testing resulting in failed chips. It can also happen due to product age or other conditions that mean the material is no longer sellable. You can define your own scrap types and processes. Previously scrapped material can be reclaimed as well if needed.
Bonusing material allows you to manually enter information or correct physical inventory goods in the system.
The most typical examples of why you would decide to use scrap and bonus versus a rework is to adjust physical inventory accounts or if you have a onetime occurrence that needs to be changed, instead of having to go back and alter the entire flow. You will scrap out some of the parts and bonus in the proper amount so that you have a more accurate reflection of your inventory account.
Here are some the variables to consider when deciding whether you should use a rework or scrap and bonus:
- Is this a one-off situation or part of the IBOM flow? If it is a part of IBOM flow you should consider using rework. For a one-off situation where you need to make a quick change in the inventory situation count – maybe you receive 30 wafers and account was slightly off or an error was done, scrap and bonus is preferred.
- Is this done on the fly or a stop and review situation? If it’s done on the fly typically you go with scrap and bonus, but if it’s a stop and review situation you may want to take a step back and consider reworking your IBOM or reviewing your setup.
- What is the costing impact? You should consider the impact on costing and the roll-down costing validation. This is where bonusing items in may affect costs.