How do you evaluate the injection molding samples and prototypes before approving mass production?

A good QMS should identify a phase in its Product Development Process (PDP) which mandates a “First Article Inspection”, or FAI. This requires the molder to measure every attribute and variable on the part, and to confirm that all cavities have consistent temperature, filling, venting, and ejection (periphery cavities can often be a bit pesky). A solid FAI would require n=5 samples per cavity to secure some sense of the average dimension for each cavity. This activity, along with performing all required material testing, assembly fit, and design functionality will constitute the mold verification portion of the PDP.

Performance. Do the prototypes accomplish performance? A big question. I've done tests were multiple material types have failed performance due to choice of material. It usually works this way with R&D. Hand in hand with the customer, R&D and the molder, material trials is common. Until then, a proper material passes all quality levels, brings the next stage of part performance.

Before running parts it can be incredibly beneficial to proactively discuss requirements with the customer. PPAP's from various industries require different information and it is recommended to perform a GR&R along with capability study of part dimensions (using different lots, presses, operators, etc) to forcibly see how things might change in mass production. It takes longer up front but if you can intentionally add variation into initial sampling it can help give lots of confidence moving to mass production components.

Essa etapa para mim é fundamental. Quando selecionamos o material de protótipo correto temos grande facilidade de correlacionar o seu desempenho com o desempenho da peça final moldada por injeção. Nessa etapa é possível validar e ergonomia, possibilidade e facilidade de montagem da peça no conjunto.

In my experience the prototypes and pilot lots are typically made out of prototype mold or bridge tooling. Before the large volume is approved the production tooling has to be tested for all the required process capabilities .

Consider the sustainability and environmental impact of the materials and processes used. Assessing the recyclability of materials and the energy efficiency of the molding process can contribute to more sustainable production practices. Additionally, it's important to analyze the supply chain for material sourcing to ensure ethical and sustainable practices. Another aspect is the lifecycle assessment of the product, understanding its environmental footprint from cradle to grave. Engaging with suppliers who are committed to reducing their carbon footprint and who use sustainable materials can align your product with growing consumer demand for environmentally responsible products.

Trabalhando com manufatura aditiva e moldagem por injeção por muitos anos, percebo que hoje o processo FDM é o ideal para validarmos o desempenho de uma peça em termoplástico moldado por injeção. Isso por conta das propriedades, características e natureza dos materiais que são muito semelhantes. Algo que não acontece no método SLA, por exemplo, por se tratar de um termofixo.