Most manufacturers have understood that placing inspectors at the end of the line is not the right way (or, at least, not sufficient) to manage quality. The key is to improve processes and to catch issues as close to their source as possible.
But, in practice, when it comes to checking quality during the manufacturing process, what are the most common options? And how to schedule them based on work orders issued by the factory’s planning system?
The goals & benefits of inspecting quality during production
The objective is to catch quality issues before it is too late and they become a larger problem:
- If issues are found, corrective actions can be implemented, and hopefully the relatively few products that have already come off the line can be re-worked without delaying the whole run.
- By catching issues early, we prevent them from happening throughout the remainder of the production run.
There is no ‘one-size-fits-all’
The way that you check quality during production will vary depending on the situation.
Let’s cover a few examples.
1. Simple product (only one level in the manufacturing BOM) and small order quantity
From a production planning perspective, this is very simple. It is usually 1 work order, which maps to 1 FAI (First Article Inspection), 1 IPQC (In-Process Quality Control) and 1 OQC (Outgoing Quality Control).
2. Simple product with a high order quantity
The ERP may issue a work order every few days. (This way, evaluating production performance is easier, and it avoid pushing put too many parts on the lines at once.)
In this case, what often makes sense is:
- 1 FAI for every batch
- Several IPQC jobs for every batch
- 1 OQC every time production sends some finished products to the warehouse – this might be more than once per work order)
3. Complicated product with small order quantity
The planning system usually issues several work orders (one for each semi-finished product) and one work order for final assembly & packing. In this case, the right approach is:
- 1 FAI for each semi-assembly
- 1 IPQC for each semi-assembly work order
- 1 OQC on finished products
4. Complicated product with large order quantity
An ERP is usually configured to do as above, and to break it into several groups of work orders (each with lower quantity).
In practice, there are different ways to implement this depending on the situation (continuous customer orders, etc.).
The QC approach is usually as follows:
- 1 FAI for each work order of semi-assembly
- An IPQC for every work order, or more frequent
- If semi-assemblies are moved into the warehouse, a product inspection point on those semi-assemblies
- 1 OQC for each final assembly & packing work order
There are obviously many special cases. But these 4 cases are a good basis to understand how QC jobs are mapped on work orders and production batches.
How do you do this in your factory?
