polymer processing

The tenth step in validating a injection mold with the overall process shown in injection mold validation flow chart is Qualification (Process Capability Study) . The steps before: 1. Mold certification 2. Dry cycle mold 3. Process stability test 4. Gage repeatability & reproducibility (R&R) test 5. Mold viscosity test 6. Balance of fill analysis 7. Gate Freeze Test 8. Commissioning (multi-cavity analysis) 9. Design of Experiments (DOE or DOX) Purpose: The purpose of the qualification study is to determine if the process can meet the specified key part tolerance ranges. The first mold being manufactured to produce a molded part might be made “metal safe”. In this case, the qualification step will determine how much metal needs to be modified in the mold. Resin and colorant properties also need to be evaluated so that process capability may be determined. Once a process has been selected from performing the Design of Experiments (DOE or DOX) , the qualification study needs t...

The eight step in validating a injection mold with the overall process shown in injection mold validation flow chart is Commissioning (multi-cavity analysis) . The steps before: 1. Mold certification 2. Dry cycle mold 3. Process stability test 4. Gage repeatability & reproducibility (R&R) test 5. Mold viscosity test 6. Balance of fill analysis 7. Gate Freeze Test Purpose: The purpose of commissioning is to ensure that all cavities in the mold deliver the same quality, i.e., there is no difference between cavities in the mold on the critical dimensions. The time required to perform this analysis is a function of the number of cavities and number of critical dimensions. The time on the injection molding machine is minimal compared to the time required to measure the parts. However, by performing this analysis it will significantly reduce the number of parts required to test and measure for future experiments on the multi-cavity tool. A solid understanding of creating and inter...

The fourth step in validating a injection mold with the overall process shown in figure injection mold validation flow chart is gage repeatability & reproducibility (R&R) test . The steps before: 1. Mold certification 2. Dry cycle mold 3. Process stability test Purpose: The purpose of the gage R&R analysis is to quantify the magnitude of variation of a measurement system. To ensure the benefit derived from using measurement data is of value and cost effective, attention must be focused on the quality of the measurement data. One of the most common reasons for low-quality data is too much variation in the measurement data. For example, a measurement system with a large amount of variation may not be appropriate for use in analyzing an injection molding process because the measurement system’s variation may mask the variation in the injection molding process. A gage is any device used to obtain measurements. This includes devices like coordinate measurement machines, verni...

The third step in validating an injection mold according to injection mold validation flow chart is dry cycle mold is process stability test . The steps before are: 1. Mold certification 2. Dry cycle mold Purpose: The purpose of the process stability test is to identify any gross mechanical design/construction flaws which will cause part variation over time. In addition, the process stability must be established with no short shots, flash, etc., prior to running designed experiments. The test is run at mid-range resin molding conditions for a period of time to allow thermal expansion equilibrium. In most instances, the mold builder may already have a process where the mold could run comfortably for several hours. During the process stability test the mold must run with one ejection stroke unless it was designed to cycle with multiple strokes. A robust ejection system will be able to eject the part and runner with one ejection stroke. Multiple ejection strokes per molding cycle incr...

To validate an injection mold, there are numerous items one must take into consideration before the mold is completed and work is ready to begin. First, it is advisable to hold a mold design review meeting with all involved parties prior to tool manufacture. Invite the mold builder, hot runner supplier, steel supplier, press supplier, resin supplier, and a strategic molder for the design review. Involving everyone early on in the process and keeping them informed throughout the building of the mold avoids needless complications. Once all the suppliers have been identified it is vital that they are all given training on the injection mold validation procedure , IMVP. The training should be done well in advance of the first mold qualification, if you have a pilot tool stage this is an ideal time. It could be done whilst the production tools are being manufactured. It is strongly advised the tool builder is made aware of the requirements of mold certification (steel measurements) before...

The following steps are required in validating a injection mold according to injection mold validation flow chart. 1. Mold certification 2. Dry cycle mold 3. Process stability test 4. Gage repeatability & reproducibility (R&R) test 5. Mold viscosity test 6. Balance of fill analysis 7. Gate freeze test 8. Commissioning (multi-cavity analysis) 9. Design of experiments 10. Qualification (process capability study) 11. Mold metal Adjustments - centering process 12. Verification (30-day run)

Does your mold balanced? There will be the part of just preparing problem for mold balancing . Fundaments with mechanism in part 2/2 which formally is the first part. How to check mold balance? The eases way is to weigh parts from mold. I suggest go to the shop floor take the full shot and weigh on the most precise available weight. Date you can compile in the form presents below. The best you can do is to take more than one shot and count the average from the same cavity. You have two ways, try both, count deviation from maximum weight (first way) and from average weight (second way) for all cavities. Formulas are in the table, where indexes; m – maximum weight from all cavities, n – weight for the variable cavity, a – average weight for all cavities. Few conclusions from the above example. Cavities 7 and 10 are extreme first is the most second the least filled. Deviation from average gives the tendency +/- from average. Cavities 9 and 10 are the worst balanced. I would a...