Managing Rejects: Why They Matter and How to Handle Them
Rejects are an unavoidable reality in manufacturing. No matter how refined your processes are, there will always be instances where parts fall short of specification—whether due to human error, material defects, equipment failure or process inconsistencies. These issues can surface at multiple points: internally during production, externally as returns from customers or upstream from suppliers delivering non-conforming components.
What matters most is how these rejects are handled. Ignoring or poorly managing them leads to increased costs, production delays and a damaged reputation. On the other hand, an effective reject management process helps maintain product quality, improves operational efficiency and protects customer relationships. By tracking, classifying and acting on rejects promptly and systematically, you can minimise their impact, identify root causes and take corrective action to prevent recurrence—ultimately driving down costs and boosting profitability.
Types of Rejects
Rejects originate from various sources, each requiring its own specific handling process. The primary sources of rejects include:
Internal Rejects: Found during your own production process.
Customer Rejects: Issues that slipped through and were caught by the customer.
Supplier Rejects: Components received from suppliers that don’t meet spec.
Customer-Supplied Parts: Free-issue components sent by the customer may need rejecting if they’re unfit for further work.
What to Do With Rejects
How you action an issue is important to reduce cost, deliver quickly and deliver the best customer satisfaction.
Concessions: Negotiate approval from the customer to use the part as-is. If granted, return it to production or deliver the finished part.
Internal Reworks: Route the part through additional operations. Build standard rework paths to streamline this.
Return to Customer: For customer-supplied parts beyond salvage. Ship them back with proper documentation.
Return to Supplier: Send unacceptable items back and request replacements or cancel from the PO.
Scrap: If nothing can be done, scrap it and start again.
Implementing Corrective Action
Beyond simple reject handling, many businesses need or choose to implement formal corrective action plans. These typically cover:
Containment: Stop the issue from spreading—quarantine suspect material or batches.
Investigation: Identify the cause; material, machinery, tooling, operator?
Corrective Action: Decide how to fix affected parts.
Preventative Action: Put systems in place to stop recurrence.
Validation: Ensure the fixes are working.
Whilst these steps work for many, you need to be able to add your own tasks to maintain action plans that work for you.
Analysing Rejects
Classification is key. Know what the issue is; paint, material, machining and drill down further. For instance, a paint reject might break into masking problems, bubbling or contamination.
With proper categorisation, trends emerge. For example you might see:
Most issues happen in milling.
The manual milling machine has more errors.
One operator is consistently linked to these operations.
From there, you take action; training, process changes or even equipment upgrades.
However, data only points you in the right direction, it doesn’t explain the “why.” For example, if errors spike Friday afternoons, the system won’t tell you if your operator’s long pub lunch is to blame, but you’ll know where to look.
Bottom Line
Rejects are more than just waste – they’re a valuable source of insight. When properly tracked and analysed they highlight weaknesses, reveal patterns and guide improvement. Managing rejects well helps cut costs, improve quality and maintain customer satisfaction. Handled correctly, reject control is not just about damage control – it’s a key part of running a more profitable and efficient operation.
TL;DR
Rejects are inevitable in manufacturing, but how you handle them makes all the difference. Tracking, classifying and addressing them properly helps reduce costs, improve quality and avoid repeat issues. Whether the reject is internal, from a customer or supplier, having clear processes – including reworks, returns, concessions or scrap – is essential. Analysing trends in rejects gives valuable insight into where things go wrong so you can fix the root cause. Done right, managing rejects drives efficiency, profitability and customer satisfaction.
