Who Can Change Process Parameters? Build Authorization, Change and Rollback Records

On the same machine, the day shift increases the temperature by five degrees, and the night shift reduces the speed by eight percent. The next day, quality fluctuates, and everyone only sees the current parameters, yet no one can explain who changed them, for what reason, how many pieces were verified, or when the changes should be reverted.

Being able to change parameters does not mean parameters are out of control. The real risk lies in unbounded modifications, lack of evidence, and no rollback path for anomalies. Establishing the following three records first is more practical than locking all buttons from the start.

Who Can Change Process Parameters? Build Authorization, Change and Rollback Records

The authorization record answers who can change, what can be changed, and under what conditions. Do not grant a general permission based solely on position; instead, classify parameters by risk level. Parameters affecting safety, quality, and equipment protection should have stricter approval and review requirements than minor cycle adjustments.

For each critical parameter, clearly define the standard value, allowable range, modifying role, approving role, and reviewing role. Operators can make minor adjustments within the range, but any changes beyond the range must be escalated. Equipment, process, and quality departments should each be responsible for their own professional judgment to avoid situations where one person both applies and approves changes.

The Authorization Account: Tracking Who Can Make Changes

The change record should not only save the 'old value' and 'new value'. It should also document the problem phenomenon, technical basis, impact on products, trial scope, start time, approver, and verification standards. This enables determining whether a modification was a planned experiment or an unconfirmed drift.

Before making changes, establish a baseline: current parameters, the most recent conforming sample, equipment status, and tooling used. After the change, limit the trial quantity and monitor quality, cycle time, and equipment load shop-floor simultaneously. Focusing only on one indicator improving may shift the cost to downstream processes.

The Change Account: Recording Process Modifications

Every temporary change must have rollback conditions documented before implementation. If the trial production fails, fluctuations exceed the upper limit, equipment produces abnormal noises, or the validation period expires, the system should revert to the confirmed baseline immediately, not discuss further shop-floor.

Rollback is not just reverting the numbers. It also requires identifying the scope of affected in-process products, isolating the trial pieces, restoring relevant work instructions and alarm thresholds, and having the next shift verify the first batch results. Otherwise, even if the interface is restored, the shop floor may still follow the old procedures.

For adjustments that cannot be rolled back immediately, clearly define temporary controls, responsible parties, and expiration dates. If no new approval is received before the deadline, stop further use. The temporary state must be visible, not hidden in personal notes or chat records.

A One-Week Minimum Trial for Testing

Start with one machine that has obvious quality variation and frequent parameter adjustments, not all machines at once. Identify ten key parameters and establish an authorization matrix. For the next week, every parameter change must go through a change card, with rollback conditions pre-filled on the card.

At the end of each shift, only review three things: whether any unauthorized changes were made, whether any temporary parameters expired, and whether products rolled back were still not isolated. If the record burden is too heavy, reduce the number of controlled parameters, not turn necessary evidence into verbal communication again.

Factory owners can forward the checklist to the plant manager and shop floor supervisor: first verify the authorization fields, second conduct random checks on the change basis, and third review the rollback results. Each card only retains necessary fields that support judgment, reducing unnecessary entries.

It is also necessary to acknowledge that job motivations are not entirely aligned. Adjustments may go unnoticed, but failures often lead to accountability. As a result, some may choose to 'do less to make fewer mistakes' or claim 'it's not my responsibility.' Clear responsibilities for receiving, transferring, escalating, handling, and closing issues enable the shop floor to reveal real changes.

Not all factories require the same approval process. Small factories may require dual signatures from team leaders and process engineers, while medium-sized factories add quality review. Mature factories already have an authorization platform and may not need paper forms, but temporary authorization and rollback deadlines still cannot be omitted.

The purpose of the three records is not to blame who pressed the button, but to ensure every adjustment has an explainable, verifiable, and recoverable boundary. The faster the parameter changes, the simpler and clearer the boundary must be, allowing the shop floor to handle issues promptly without passing risk to the next shift.

I am Huang Chaoxing, inventor of the TreeMES stack-light MES system. Follow me for more practical factory-management methods.