Whenever MICROingranaggi ships a product, the responsibility is ours. Always.
If a component is non-conforming and causes a problem, that problem starts here. This applies to us just as it does to any other manufacturer, and it is precisely why quality control cannot be regarded as something performed merely because the customer requires it, nor as a final formality carried out at the end of production.
Whether we like it or not,
quality control is a necessary cost of manufacturing.
I deliberately refer to it as a cost because inspection inevitably requires time, resources, and money. Consequently, the fewer parts we need to inspect, the better—provided one fundamental condition is always met: every component delivered to the customer must fully comply with specifications.
Although this may sound obvious, in practice it is not always the case.
If quality control is essential in manufacturing in general, it becomes even more critical in precision micromechanics, where the margin for error is, by definition, extremely small. When working to tolerances measured in just a few microns, there are no insignificant details. Every variable has the potential to affect the final result. This is one of the most demanding—and often least visible—aspects of our work.
When even the smallest variation can trigger a problem, identifying the root cause of a non-conformity resulting from several contributing factors becomes extremely challenging.
Determining the origin of the problem, understanding how much each factor contributed, and then reproducing the same conditions is rarely straightforward. In many cases, different combinations of variables generate different issues, and even decades of experience cannot always provide an immediate explanation.
When a non-conformity originates upstream—in the raw material or the semi-finished blank—the available corrective options become extremely limited. If the material already contains defects before machining begins, the process starts at a disadvantage, because manufacturing operations can only rarely compensate for even very small imperfections.
The path toward quality should therefore begin long before machining itself.
From supplier selection and incoming inspection of semi-finished materials, through storage conditions and cutting tool management, the objective is to prevent variability from affecting the manufacturing process.
At the same time, however, excessive inspection at the beginning of the process inevitably increases lead times and costs. The challenge is therefore to find the right balance between risk, inspection cost, and the required level of product quality, recognizing that not every component requires the same degree of monitoring.
In metrology, there is a well-established principle: the primary focus should always be on controlling the manufacturing process itself.
When the process is truly under statistical control, inspection frequency can be significantly reduced, providing a direct benefit in terms of manufacturing cost.
Achieving this level of process stability, however, generally requires high-volume, repeatable production—something that often conflicts with the production profile of many precision engineering companies, including MICROingranaggi. This is one of the reasons why our metrology department is constantly under pressure.
Inspection strategies are based on several factors, each carrying a different weight: the required tolerances, the criticality of the component, its application sector, the historical occurrence of defects, and only afterwards the reliability of the supplier.
Supplier reliability appears lower on the list for a reason. Supplier selection is itself the outcome of a thorough qualification process, based on an in-depth understanding of each supplier’s capabilities, manufacturing technologies, and equipment. This allows us to determine from the outset where attention should be focused and what level of inspection is appropriate.
Ultimately, quality control almost always remains a cost—a necessary part of manufacturing that cannot be avoided.
Inspection requirements must be determined according to the criticality of the component, and it is not uncommon for the cost of inspection to exceed the cost of manufacturing the part itself. That is simply part of the business, especially when the objective is to minimize risk rather than pass it downstream to the customer.
