Scientific Molding Documentation: What Records to Keep and Where

The Core Studies and What Each Proves

Scientific molding, popularized through decoupled molding approaches and training from groups such as RJG, separates filling from packing so the process depends on plastic behavior, not press quirks. Each study answers a question: the viscosity curve finds the fill speed where viscosity is stable, pressure drop shows how much pressure the system needs, gate seal finds the minimum hold time that stops weight gain, and cooling time studies set the minimum safe cool. Together they define a window that tolerates normal lot variation.

• Viscosity curve: relative viscosity versus fill speed, to choose a stable fill rate
• Pressure drop: pressure loss through nozzle, runner and cavity, to check press capability
• Gate seal: part weight versus hold time, to set packing duration
• Cooling study: part dimensions or ejection behavior versus cool time
• Process window: DOE across temperature, speed and pack to show the stable region

What a Complete Mold Process File Contains

For each mold, keep one process file that a technician from another shift can use without a call. It should include the study results with raw data and plots, the final setup sheet with decoupled parameters (fill speed, transfer position, pack pressure and time, cushion, melt and mold temperatures, cooling), the resin and lot used, the press and shot size used, and the monitoring limits. Add cavity pressure curve screenshots if the plant uses sensors, plus the sign-off of who approved the process and when.

Documentation That Auditors and Customers Ask For

Automotive customers under IATF 16949 expect control plans and process monitoring evidence, and medical customers expect documented process validation (IQ, OQ, PQ) under their quality system. In both cases, scientific molding records serve as the OQ evidence: they show the operating range was challenged and the product remained in specification. Link the process file to the control plan, the mold qualification report and the first article inspection so the audit trail runs from material to part.

• Process window study as OQ evidence for medical programs
• Setup sheet revision control tied to ECNs and customer approvals
• Material lot and dryer records tied to each production run

Where These Records Go Wrong

The usual failures are mundane. Studies are done once at tryout, saved on a laptop, and never linked to the mold. Setup sheets exist in three versions and the floor uses the oldest.

Data from a different press is applied without a transfer study. When scrap rises, the technician changes pack and temperature because nobody can find the original window. Store the file against the mold in your document system or ERP, control revisions, and print or display the current sheet at the press.

How AI Helps With Retrieval and Drafting

A private AI assistant over your process files can answer questions like what was the approved pack time on mold 4417 on press 9, or show me every study for this resin lot family. It can also draft the process file summary from raw study data for the process engineer to review. Netray builds this on your own documents and ERP, on premises if your customers require it.

The engineer still runs and judges the studies, and AI should not change validated setpoints.

When Full Scientific Molding Is Overkill

For simple, non-critical commodity parts with wide tolerances, a full decoupled study per mold may cost more than it saves. Use a lighter process sheet and reserve full studies for tight tolerance, high volume, regulated or high-scrap programs. Even in simple work, a documented setup sheet with revision control is worth having.