Checklist: Verifying Molder Audit Readiness for New Parts

Why audit readiness matters before you release a new part

A supplier audit is not a formality. It is a verification of the molder’s ability to hold the quality level you need. If the molder cannot show how they control a process, you are buying risk. This risk shows up later as rework, field returns, or production stoppages.

The audit readiness checklist below is designed for buyer-led audits. It is not a certification checklist. Certificates are easy to verify. Audit readiness is about whether the system actually works on the floor.

Many molders have a good quality manual. Very few can show you the last five first article inspection reports and the corrective actions that followed. The gap between the manual and the live records is where most supplier failures hide.

This checklist is grouped by theme. Each item includes a short explanation of what to check and a red flag to watch for. Use it as a working document. Print it, bring it to the audit, and mark items as verified or failed.

Quality documentation: what to pull and what to look for

Quality documentation is the backbone of a molder’s audit readiness. Without it, you cannot trace a problem back to a root cause. Without it, you cannot verify that the molder followed the process you agreed to.

Pull the following documents from the last 90 days of production. Do not accept the “master” copies. Ask for the records that were actually generated during production.

1. Control plans. These define the critical and special characteristics for each part. Check that they are current. A control plan that was written for a prototype run but never updated for production is a red flag.
2. First article inspection reports. These verify that the first part from a new setup meets the drawing. Check that the inspection was done by a qualified person, not the machine operator alone.
3. In-process inspection records. These show that the molder is checking dimensions, weight, or appearance during the run, not just at the start and end.
4. Non-conforming material reports. These document defects found during production and how they were handled. A molder that finds a lot of defects and discards them without a report is hiding a process problem.
5. Corrective action reports. These show that when a problem was found, the molder investigated the root cause and took action. Check that the action was implemented and that the problem did not recur.

Red flags:

• Control plans are handwritten or typed on a single sheet that has been re-used for multiple parts.
• First article reports are signed by the same person who set up the machine.
• Non-conforming material reports have blank sections for “disposition” or “root cause.”
• Corrective actions are “prevent recurrence” without a specific, verifiable action.

A molder that cannot produce these documents in a reasonable time is not audit ready. They may have the capability, but they do not have the discipline.

Process control: checking the actual machine and parameters

Documentation is only useful if it reflects what is happening on the machine. During the audit, walk the floor. Watch the machines. Ask the operator to show you the current process parameters.

Check the following:

1. Injection parameters. Pressure, temperature, injection speed, and holding time. These should match the control plan. If the operator is running different parameters than the plan, ask why. Is it a temporary fix? A permanent change?
2. Cavity temperature and mold temperature. These affect part dimensions and surface finish. Check that the mold temperature is stable. Fluctuating mold temperatures are a common cause of dimensional drift.
3. Material drying. If the molder is running a hygroscopic resin like ABS or nylon, check the drying process. Ask to see the material drying records. Are they drying the material for the right time at the right temperature?
4. Machine maintenance logs. Check that the machine is being maintained. Look for records of lubrication, hydraulic service, and dielectric heating checks. A poorly maintained machine produces variable parts.
5. Gauges and calibration. Check that the gauges used for in-process inspection are calibrated. Look for calibration stickers with dates. If a gauge has no date, it is not calibrated.

Red flags:

• The operator has a piece of paper with “current settings” that differs from the control plan.
• The material is sitting in the hopper for hours without a drying record.
• The machine has a visible leak or a worn dielectric heater.
• The operator cannot explain why a particular parameter is set at a specific value.

A molder that controls the machine well will not be afraid to show you the parameters. They will not hide behind the “operator knows best” defense.

Traceability: linking material lots to finished parts

Traceability is how you prove that a specific part was made from a specific lot of material. If a problem appears in the field, you need to know exactly which material lot was used, which machine made it, and when.

Check the following:

1. Raw material lot numbers. Ask the molder to show you the raw material receipts. Check that the lot number is recorded on the production order.
2. Machine and cavity numbers. Check that the production order records which machine and which cavity produced the part. If a molder runs the same part on multiple machines, this is critical.
3. Operator and inspector names. Check that the production order records who ran the machine and who inspected the parts.
4. Date and time stamps. Check that the records have date and time stamps. A record that only says “May” is not traceable. You need the exact day and time.

Red flags:

• The molder cannot show you the raw material lot for a part that shipped last week.
• The production order does not list the machine number.
• The same operator is credited with running multiple machines in the same hour.

A molder with weak traceability cannot prove that their parts are from the material they claim. This is a major risk for regulated industries.

Corrective action and continuous improvement

A molder that finds problems and fixes them is a molder that improves. A molder that finds problems and hides them is a molder that will keep making the same mistake.

Check the following:

1. Corrective action log. Ask to see the log of all corrective actions taken in the last six months. Check that each action has a date, a responsible person, and a closure date.
2. Root cause analysis. Check that the root cause is not just “operator error.” A root cause of “operator error” is not a root cause. It is a symptom. The root cause is usually in the process, the tooling, or the material.
3. Effectiveness check. Check that the molder verified the corrective action worked. A corrective action that was implemented but the problem recurred is a failed corrective action.
4. Preventive action. Check that the molder is taking actions before problems happen. This includes tooling maintenance, material changes, and process changes.

Red flags:

• Corrective actions are closed without evidence.
• The same root cause appears in multiple corrective actions.
• The molder says “we will be more careful” as a corrective action.
• There are no preventive actions on the log.

A molder that treats corrective action as a paperwork exercise will not improve their process. They will just keep making the same mistakes with better documentation.

Audit execution: how the molder handles the audit itself

The audit is not just about what the molder has. It is about how they handle the audit. A molder that is nervous, evasive, or defensive is not audit ready.

Check the following:

1. Responsiveness. Does the molder respond to your audit request quickly? Do they provide documents in a reasonable time? If they take two weeks to send a first article report, they will take two weeks to fix a problem.
2. Transparency. Does the molder show you the problems? If they only show you the successes, they are not transparent. A good molder will show you the non-conforming material reports and the corrective actions.
3. Communication. Does the molder explain the process clearly? Do they answer questions directly, or do they give vague, corporate-speak answers?
4. Follow-up. After the audit, does the molder provide a written summary of findings and actions? Do they close out the actions on time?

Red flags:

• The molder says “we will get back to you” for every question.
• The molder shows you the “best” machine and hides the ones that are struggling.
• The molder gets defensive when you ask about a non-conforming report.
• The molder does not provide a follow-up summary.

A molder that handles the audit well will treat it as a partnership. They will want to show you how they work. They will not be afraid of the questions.

Common gaps that indicate weak audit readiness

After walking through the checklist, you will likely find some gaps. The following are the most common gaps that indicate a molder is not audit ready.

Gap	What it looks like	Why it matters
Stale control plans	Control plan was written for a prototype, never updated	The molder is running the process based on outdated information
Missing traceability	No raw material lot on the production order	You cannot trace a problem back to the material
Verbal overrides	Operator runs different parameters than the plan	The process is not controlled, and quality is inconsistent
No corrective action evidence	Corrective actions are closed without proof	The molder is not fixing the root cause, just the symptom
Untrained inspectors	Inspector is also the machine operator	The inspection is biased and not independent
No preventive maintenance	Machine has no maintenance log	The machine will break, and production will stop

These gaps are not minor. They are the signs of a molder that is not ready to take on new parts. They will make mistakes, and they will not be able to prove that they are fixing them.

How to use this checklist in your audit

This checklist is a working tool. Do not just read it. Use it.

1. Before the audit. Send the checklist to the molder. Ask them to prepare the documents listed. This is not a trap. It is a professional request. A molder that is audit ready will not mind. A molder that is not audit ready will struggle.
2. During the audit. Walk the floor. Pull the documents. Check the machine parameters. Talk to the operators and inspectors. Ask them to show you the last non-conforming report.
3. After the audit. Write a summary of your findings. List the items that passed and the items that failed. Give the molder a deadline to close out the failed items. Follow up on the deadline.

This process is not a one-time event. It is a relationship. If the molder passes the audit today, they will not pass it in six months unless they continue to improve. The checklist is your way of keeping them honest.

The bottom line is simple. Audit readiness is not about certificates. It is about live records, controlled processes, and a culture of problem-solving. If the molder cannot show you how they control quality, do not release the new part. Find a molder who can.