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Tool Wear FAQs

Questions and Answers re Correlation Master™ and Tool Wear

Q1:  Does Correlation Master (CM) need to be rerun after tool dimensional adjustments in case the dimensional adjustments have an impact on flow conditions and subsequently the Operating Range and/or Operating Target?

A1:  No. It is not necessary to redo the Induced Variation Study (IVS) to determine if the tooling dimensional adjustments have an impact on flow conditions. Any changes to the tooling to achieve dimensional compliance are third or higher order changes to the plastic flow path and have no measurable impact on other dimensions within that cavity or on any other dimension in any other cavity.

Q2:  Does tooling have to be adjusted more than one time when CM is used in order to get dimensional compliance?

A2:  No. Algoryx provides the definitive answer on how tooling—each dimension in each cavity—should be adjusted in order to bring each dimension into the spec. box and meet tolerance requirements. This single, optimum tooling adjustment includes all combinations of press settings within the process window. Algoryxdoes not make the decision for you whether to adjust tooling or relax tolerances. Algoryxdoes tell you what the optimum tooling adjustment is once you have made the decision to adjust tooling. You only have to make the tooling adjustment once instead of several times.

Q3:  How do you verify that tooling adjustments were done properly?

A3-1:  There are two ways to verify that the tooling adjustment was done properly. First, the toolmaker can measure the physical dimension(s) in the changed cavity(ies) to ensure compliance with the changed tool drawing.

A3-2:  Second, part dimensions can be measured from 3 shots and added to the CM data set. The location of the new data points on the correlation charts will confirm (or not) that the tool tuning was done correctly.

Q4:  How does Algoryx help me understand the impact of tool wear?

A4:  Algoryx provides you with the technology to:

1. Determine if tool wear is a problem;
2. Make the determination if tool wear is a problem without taking the tool off of the press; and,
3. If tool wear is a problem, to identify, IN ADVANCE, when you will start producing bad parts; thus,
4. Schedule preventative maintenance (PM) proactively rather than reactively.

Molders do not operate in a vacuum. They are familiar with the wear rates of different material (including glass-filled materials) on different grades of steel/aluminum/etc. Some molds last tens or hundreds of thousands of cycles before they need PM. Other molds wear out quickly. Either way, Algoryx provides you with an answer.

Q5:  How does the Operating Range change as the tool wears?

A5:  Please note the immediately below figure. It is from the Algoryx training presentation. The slide shows how the Operating Range decreases—as a result of tool wear—as the number of machine cycles increases. With little tool wear, the arrow will have a relatively flat slope. With high tool wear, the arrow will have a relatively steep slope. Bad parts will be produced at the point—number of machine cycles—where the arrow (Operating Range) crosses zero and changes from a positive to a negative value.

Q6:  How and when do you determine OR1 and OR2?

A6-1:  The initial value of the Operating Range (OR1) is determined during the initial CM study.

A6-2: OR2 is determined after the tool has been through a certain number of cycles. The molder decides how long to wait before determining OR2. Simply measuring the dimensions from a single shot can establish an indication of the rate of tool wear and whether or not it is time to determine the value of OR2.

It may not necessary to do a complete IVS (9×3 or 5×5) to establish OR2. Instead, do a Mini-IVS (MIVS). Simply measure 3 shots (min, max, nom, for example) from each of 3 setups to establish OR2. The 3 setups would typically be chosen to give data points at the left-hand end, the center and the right-hand end of the regression line. Further, these 3 setups already exist from the OR1 study so no new factors or levels need to be determined.

Data scatter affects the Operating Range. If the original IVS charts show substantial data scatter around the regression line, then Algoryx suggests that you repeat the IVS (9×3 or 5×5) to determine OR2 and subsequent Operating Ranges.

Q7:  Can Algoryx help me manage the risk associated with tool wear?

A7:  Yes. The ability of Algoryx to proactively determine when PM is needed is an important risk mitigation and risk management tool.

Q8:  Should CM be rerun when all inserts are replaced?

A8:  Yes. If all mold inserts were replaced with new inserts because of tool wear, then, in essence, you would have a new mold. The correlation study should be repeated with the “new” mold. The new mold would have a new Operating Range and a new Operating Target. Using CM to determine the new Operating Range and Operating Target is a 100% confidence approach.

Q9:  Can CM help me identify when flash is starting to occur?

A9:  Yes. Barring any unusual (and undesirable) circumstances—such as shorts, flash, pin-push deformation and an incapable measurement system—the data points are tightly clustered around linear regression lines. Abnormal circumstances show up immediately as deviant data patterns on the correlation charts. Contact Algoryx for more information.

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