Showing posts with label injection moldng. Show all posts
Showing posts with label injection moldng. Show all posts
Injection molding machine platen daylight
Platen Daylight - Open - Maximum and Minimum open distance; closed - Maximum and Minimum shut distance.
Injection molding machine platen
Injection molding machine platen - The plates on which the mold assembly is mounted. Large metal blocks on clamping ends of a molding machine used to support the mold.
Setting up manual cycle in injection molding
Manual cycle - A manual cycle requires that each machine function be controlled manually by an operator.
Low pressure injection mold close
Low pressure mold close - Low pressure mold closing is a provision in the machine to lower the clamp closing force during the clamp closing cycle. The lower clamp forces minimizes the danger of mold damage caused by parts caught between the mold faces.
Knockout injection molding
Knockout - Any part or mechanism of a mold used to eject the molded article.
In-Mold Decorating for extrusuion and injection molding
In-Mold Decorating - The process of applying labels or decorations to plastic articles simultaneously with the molding operation.
Injection molding pressure
Injection Pressure - Pressure exerted on plastic to flow through a manifold and die head tooling.
Flash plastic part
Flash - The thin, surplus web of material which is forced into crevices between mating surfaces during a molding operation, and which remains attached to the molded article.
Process stability test injection molding
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. If this is the case, skip to step 10.
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 increases the wear on the ejection system and increases the molding cycle.
All the steps during the procedure that involve intimate contact with the injection molding machine are to be done by a qualified injection molding machine operator.
Procedure:
1. Set melt temperature to resin manufacturer's recommended mid-range.
2. Set mold temperature to resin manufacturer's recommended mid-range.
3. Set hold pressure and time to zero, as well as pack time and pressure.
4. Set cooling time long enough so that parts eject consistently without distorting.
5. Adjust feed stroke and screw/ram position cutoff so that parts fill approximately 95% during injection.
6. Set adequate hold time and pressure, as well as pack time and pressure, so no sink marks are visible.
7. Record process settings of the machine, melt temperature and mold temperature.
8. Run the process long enough that you feel comfortable the mold and process has reached steady state, and there are no functional issues with the mold.
9. Evaluate visually for any gross part or mold variation, e.g., flash, short shots, scratches, blemishes, water (leakage) and voids.
10. Collect one full shot and weigh each part. Record individual part weight.
• Note: This will be used as the weight of a full part when determining 90% part weight during the following tests.
11. Explore the processing window of the mold. Vary parameters such as injection rate, hold pressure, hold time, cooling time in order to begin to understand the mold processing window. For each range of process settings collect at least one set of parts. These parts will be necessary to perform the gage R&R analysis. Recall for the gage R&R one is trying to minimize the variation within a sample but maximize the variation between samples.
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 increases the wear on the ejection system and increases the molding cycle.
All the steps during the procedure that involve intimate contact with the injection molding machine are to be done by a qualified injection molding machine operator.
Procedure:
1. Set melt temperature to resin manufacturer's recommended mid-range.
2. Set mold temperature to resin manufacturer's recommended mid-range.
3. Set hold pressure and time to zero, as well as pack time and pressure.
4. Set cooling time long enough so that parts eject consistently without distorting.
5. Adjust feed stroke and screw/ram position cutoff so that parts fill approximately 95% during injection.
6. Set adequate hold time and pressure, as well as pack time and pressure, so no sink marks are visible.
7. Record process settings of the machine, melt temperature and mold temperature.
8. Run the process long enough that you feel comfortable the mold and process has reached steady state, and there are no functional issues with the mold.
9. Evaluate visually for any gross part or mold variation, e.g., flash, short shots, scratches, blemishes, water (leakage) and voids.
10. Collect one full shot and weigh each part. Record individual part weight.
• Note: This will be used as the weight of a full part when determining 90% part weight during the following tests.
11. Explore the processing window of the mold. Vary parameters such as injection rate, hold pressure, hold time, cooling time in order to begin to understand the mold processing window. For each range of process settings collect at least one set of parts. These parts will be necessary to perform the gage R&R analysis. Recall for the gage R&R one is trying to minimize the variation within a sample but maximize the variation between samples.
Dry cycle injection mold
The purpose of the dry cycle mold is to evaluate the mold mechanical actions for any gross problems prior to injecting plastic into the mold. The machine operator at the mold builder or molder should know how to adjust the settings on the injection unit to cycle the mold without injecting plastic into the tool. If at anytime during the dry cycle procedure there is a possibility that damage is being done to the tool or if the mold is not operating as designed, pull the mold from the press and have it examined by an experienced mold builder.
This stage is often carried out prior to the customer eing invited to the mold builder for the debug. If there are any machine/mold operation issues it is preferable for the mold builder to remedy this before attendance, saving unnecessary travel. If there is a serious mold design flaw (as opposed to a mold assembly issue) it will then be necessary to attend to discuss next steps.
All the steps during the procedure that involve intimate contact with the injection molding machine are to be done by a qualified injection molding machine operator.
Procedure:
1. Put mold in press. Ensure that the cooling circuits are attached to the mold and that water is circulating through the mold. Also, if there is a hot runner manifold have the controller installed and temperature heaters turned on.
2. Verify water is flowing through the mold at resin manufacturer’s recommended mid-range; check with flow meter indicator or measure flow rate by having the returns empty into a bucket. Ensure heaters are working in the hot runner system by reading the thermocouple outputs.
3. Close the mold at a slow rate and pressure to verify that the mechanical, pneumatic or hydraulic actions of the mold have responded and are moving as designed. Listen for any suspect noises of possible binding of slides or galling.
4. Clamp up on the mold at a low tonnage. Be sure to have mold protection time, pressure and rate properly set so that no major damage can be done to the mold.
5. When the mold is in the press, open the mold at a slow rate to ensure that the mechanical, pneumatic or hydraulic slides are responding and moving as designed. Listen for any suspect noises of possible binding or galling. The slides should move with little resistance.
6. After mold is completely open, cycle the ejector plate manually at a low pressure and low rate, while visually inspecting to verify the ejector plate is performing as designed.
7. Cycle the mold without injecting plastic. Typically this is done by transferring from fill/pack stage to hold stage by position and setting the feed stroke and transfer position to the same position while having the hydraulic pressure set to 0 bar. Keep the clamp open/close rates and pressures to a minimum. Set the hold time to zero. Set cool time to a minimum machine value to decrease the cycle of the mold.
8. Evaluate the mold while it is cycling for any gross mechanical problems. Study the movements of the mold for possible binding or galling of slides, ejector pins and leader pins.
9. Increase the rate and pressure of mold open/close slowly until it replicates the speed and pressures expected during production or sampling. Also do the same with the ejection action.
10. Increase the tonnage slowly until it replicates the tonnage necessary to keep the mold closed during the injection stage of the molding process.
11. Continue cycling the mold until you determine that mechanically there are no fundamental flaws with the production or design of the mold.
This stage is often carried out prior to the customer eing invited to the mold builder for the debug. If there are any machine/mold operation issues it is preferable for the mold builder to remedy this before attendance, saving unnecessary travel. If there is a serious mold design flaw (as opposed to a mold assembly issue) it will then be necessary to attend to discuss next steps.
All the steps during the procedure that involve intimate contact with the injection molding machine are to be done by a qualified injection molding machine operator.
Procedure:
1. Put mold in press. Ensure that the cooling circuits are attached to the mold and that water is circulating through the mold. Also, if there is a hot runner manifold have the controller installed and temperature heaters turned on.
2. Verify water is flowing through the mold at resin manufacturer’s recommended mid-range; check with flow meter indicator or measure flow rate by having the returns empty into a bucket. Ensure heaters are working in the hot runner system by reading the thermocouple outputs.
3. Close the mold at a slow rate and pressure to verify that the mechanical, pneumatic or hydraulic actions of the mold have responded and are moving as designed. Listen for any suspect noises of possible binding of slides or galling.
4. Clamp up on the mold at a low tonnage. Be sure to have mold protection time, pressure and rate properly set so that no major damage can be done to the mold.
5. When the mold is in the press, open the mold at a slow rate to ensure that the mechanical, pneumatic or hydraulic slides are responding and moving as designed. Listen for any suspect noises of possible binding or galling. The slides should move with little resistance.
6. After mold is completely open, cycle the ejector plate manually at a low pressure and low rate, while visually inspecting to verify the ejector plate is performing as designed.
7. Cycle the mold without injecting plastic. Typically this is done by transferring from fill/pack stage to hold stage by position and setting the feed stroke and transfer position to the same position while having the hydraulic pressure set to 0 bar. Keep the clamp open/close rates and pressures to a minimum. Set the hold time to zero. Set cool time to a minimum machine value to decrease the cycle of the mold.
8. Evaluate the mold while it is cycling for any gross mechanical problems. Study the movements of the mold for possible binding or galling of slides, ejector pins and leader pins.
9. Increase the rate and pressure of mold open/close slowly until it replicates the speed and pressures expected during production or sampling. Also do the same with the ejection action.
10. Increase the tonnage slowly until it replicates the tonnage necessary to keep the mold closed during the injection stage of the molding process.
11. Continue cycling the mold until you determine that mechanically there are no fundamental flaws with the production or design of the mold.
Clamp stroke
Clamp stroke - The maximum travel distance the opening and closing mechanism can traverse the platens.
Clamp Opening Force
Clamp opening force - The maximum force in tons (2,000 pounds) possible to exert upon the molds at the initiation of opening.
Clamping Force
Clamping force - The maximum force in tons (2,000pounds) exerted upon the molds when closed and held against blowing pressure.
Clamp Speed injection molding
Clamp Speed - Speed at which the mold platens will open and close; controlled by operator settings.
Charge injection molding
Charge - The amount of material volume or weight required for the injection unit to plasticize for each molding cycle.
Injection molding tryout and qualification
PROCESS
This is the marriage of mold, material, and machine into an on-going process to continuously manufacture a part of consistent dimensions and physical characteristics.
TRYOUT
This is the initial test of a mold to check and repair any mechanical or dimensional defects. Once the mold is proven mechanically, the next tryout’s purpose is to optimize the molding cycle and obtain parts of sufficient quality and quantity for submission for testing and approval. A tryout is never a qualification run.
QUALIFICATION
A qualification run is a sustained run to show the mold and process can consistently produce parts of acceptable quality. This is generally understood to be a sustained run with little or no adjustments after the mold is brought on-cycle for a period of hours. Since this must be done for a sustained time, it can only be done after the parts produced from the tryout have been approved.
STARTUP
This is taking the conditions identical to those approved during the qualification run, translating them to a production machine and beginning a production run.
This is the marriage of mold, material, and machine into an on-going process to continuously manufacture a part of consistent dimensions and physical characteristics.
TRYOUT
This is the initial test of a mold to check and repair any mechanical or dimensional defects. Once the mold is proven mechanically, the next tryout’s purpose is to optimize the molding cycle and obtain parts of sufficient quality and quantity for submission for testing and approval. A tryout is never a qualification run.
QUALIFICATION
A qualification run is a sustained run to show the mold and process can consistently produce parts of acceptable quality. This is generally understood to be a sustained run with little or no adjustments after the mold is brought on-cycle for a period of hours. Since this must be done for a sustained time, it can only be done after the parts produced from the tryout have been approved.
STARTUP
This is taking the conditions identical to those approved during the qualification run, translating them to a production machine and beginning a production run.
Injection molding tryout and qualification
PROCESS
This is the marriage of mold, material, and machine into an on-going process to continuously manufacture a part of consistent dimensions and physical characteristics.
TRYOUT
This is the initial test of a mold to check and repair any mechanical or dimensional defects. Once the mold is proven mechanically, the next tryout’s purpose is to optimize the molding cycle and obtain parts of sufficient quality and quantity for submission for testing and approval. A tryout is never a qualification run.
QUALIFICATION
A qualification run is a sustained run to show the mold and process can consistently produce parts of acceptable quality. This is generally understood to be a sustained run with little or no adjustments after the mold is brought on-cycle for a period of hours. Since this must be done for a sustained time, it can only be done after the parts produced from the tryout have been approved.
STARTUP
This is taking the conditions identical to those approved during the qualification run, translating them to a production machine and beginning a production run.
This is the marriage of mold, material, and machine into an on-going process to continuously manufacture a part of consistent dimensions and physical characteristics.
TRYOUT
This is the initial test of a mold to check and repair any mechanical or dimensional defects. Once the mold is proven mechanically, the next tryout’s purpose is to optimize the molding cycle and obtain parts of sufficient quality and quantity for submission for testing and approval. A tryout is never a qualification run.
QUALIFICATION
A qualification run is a sustained run to show the mold and process can consistently produce parts of acceptable quality. This is generally understood to be a sustained run with little or no adjustments after the mold is brought on-cycle for a period of hours. Since this must be done for a sustained time, it can only be done after the parts produced from the tryout have been approved.
STARTUP
This is taking the conditions identical to those approved during the qualification run, translating them to a production machine and beginning a production run.
Injection molding tryout and qualification
PROCESS
This is the marriage of mold, material, and machine into an on-going process to continuously manufacture a part of consistent dimensions and physical characteristics.
TRYOUT
This is the initial test of a mold to check and repair any mechanical or dimensional defects. Once the mold is proven mechanically, the next tryout’s purpose is to optimize the molding cycle and obtain parts of sufficient quality and quantity for submission for testing and approval. A tryout is never a qualification run.
QUALIFICATION
A qualification run is a sustained run to show the mold and process can consistently produce parts of acceptable quality. This is generally understood to be a sustained run with little or no adjustments after the mold is brought on-cycle for a period of hours. Since this must be done for a sustained time, it can only be done after the parts produced from the tryout have been approved.
STARTUP
This is taking the conditions identical to those approved during the qualification run, translating them to a production machine and beginning a production run.
This is the marriage of mold, material, and machine into an on-going process to continuously manufacture a part of consistent dimensions and physical characteristics.
TRYOUT
This is the initial test of a mold to check and repair any mechanical or dimensional defects. Once the mold is proven mechanically, the next tryout’s purpose is to optimize the molding cycle and obtain parts of sufficient quality and quantity for submission for testing and approval. A tryout is never a qualification run.
QUALIFICATION
A qualification run is a sustained run to show the mold and process can consistently produce parts of acceptable quality. This is generally understood to be a sustained run with little or no adjustments after the mold is brought on-cycle for a period of hours. Since this must be done for a sustained time, it can only be done after the parts produced from the tryout have been approved.
STARTUP
This is taking the conditions identical to those approved during the qualification run, translating them to a production machine and beginning a production run.
Polymer and plastic material
In injection molding there are two major classifications: Thermosets – compounds that go through a chemical reaction when exposed to heat and crosslink into the molded part. The second classification is Thermoplastics – compounds that are only melted, injected and cooled into their new shape of the molded product. Thermoplastics come in two (sometime three) sub classifications: Amorphous – those polymers with no discrete molecular geometry, Crystalline – those with fixed polymer geometry, and Semi-Crystalline – polymers possessing both crystalline and amorphous properties.
Mold polymer processing
A mold is literally the hole into which the plastic is injected to form the part. It must be vented enough to let the air out that is displaced by the plastic, stable enough to not distort under the pressures and heats of processing, have an adequate fill system of sprues and runners, and it must fill evenly.
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