plastic molded part with knit line blemish on side of foot or hand

Scary Plastic Part Defects and How to Avoid Them- plastic molded part with knit line blemish on side of foot or hand ,Short shot – An incomplete part due to lack of a filled mold. This problem is often attributed to a blockage or improper injection pressure. Warping – A part with a distorted shape can be due to a poor cooling system in the mold. When the plastic material is cooled unevenly, the result is a bowing effect. Most of the defects listed here can ...Injection Molding Troubleshooting: How to Avoid Knit LinesKnowing what causes the knit lines is key for troubleshooting and avoiding them. Keeping the proper temperature in the injection molding machine, runners, and within the mold are all key to ensuring the plastic flows at a speed that allows it to fuse with other flows as well as to reach all the spaces within the mold itself.



What are Parting Lines and Weld Lines in Plastic Injection Molding

Dec 14, 2017·A weld line refers to a line, notch or color change that is created on the molded part caused by the convergence of two separate flows of molten plastic. This occurs wherever there is a hole, notch, or any other feature on a part which divides the flow of plastic into 2 separate “flow fronts.”. As these flow fronts come together on the ...

What Are Knit Lines In Injection Molding? - Rex Plastics

Knit lines, weld lines, mold lines, or flow lines in injection molding are faint lines that become visible on certain plastic parts. Weld lines may appear like seams or scratches, but that is not what they are. Wavy lines are another feature of weld lines. In injection molding, it is often important to maintain consistent color throughout the part.

Knit Line Affect On Material Strength - Eng-Tips Forums

Aug 19, 2007·In a reasonable design a weld line will typically be 80% or better. Some variables are:- Temperature of the melt at the flow fronts where the two fronts meet. Pressure of the …

Injection Molding And Plastic Part Design-Total FREE CONSULT

Designers avoid significant drafts when creating products since it alters the aesthetics and reduces the volume of the final product. Plastic moldings, on the other hand, often make use of drafts in order to prevent ejection problems and overly complex tooling designs. Specifying angles on ribs is very important.

What to Do About Weak Weld Lines | Plastics Technology

Apr 01, 2008·Increasing pack or hold pressure helps to eliminate low-pressure conditions at the weld line. Another tactic to promote more chain entangling at the weld line is to raise the mold temperature 10° C (50° F). Molders should make sure the weld line is formed during the first-stage filling of the part, if possible.

Injection Molding Troubleshooting: How to Avoid Knit Lines

Knowing what causes the knit lines is key for troubleshooting and avoiding them. Keeping the proper temperature in the injection molding machine, runners, and within the mold are all key to ensuring the plastic flows at a speed that allows it to fuse with other flows as well as to reach all the spaces within the mold itself.

What are Parting Lines and Weld Lines in Plastic Injection Molding

Dec 14, 2017·A weld line refers to a line, notch or color change that is created on the molded part caused by the convergence of two separate flows of molten plastic. This occurs wherever there is a hole, notch, or any other feature on a part which divides the flow of plastic into 2 separate “flow fronts.”. As these flow fronts come together on the ...

Knit Lines,Weld lines

Sep 12, 2012·On September 12, 2012 In plastic mold knit lines (Weld lines) Weld lines occur where two flow fronts meet and always provide a source of weakness as the two fronts do not knit together. Weld lines often leave witness marks in the moulding surface. Two major sources of weld lines are multiple gating and flow around pins.

Knit Lines in Plastic Enclosures: What Are They and What

Nov 25, 2009·The lower temperature causes the knit line to have a marginally lower strength compared to the balance of the molded part. Implications. Knit lines are sometimes …

Injection Molding Troubleshooting: How to Avoid Knit Lines

Knowing what causes the knit lines is key for troubleshooting and avoiding them. Keeping the proper temperature in the injection molding machine, runners, and within the mold are all key to ensuring the plastic flows at a speed that allows it to fuse with other flows as well as to reach all the spaces within the mold itself.

Weld Line Defects in injection molding - Plastic Mold

Weld line defects in injection molding is a line or lines on the part surface that caused the part looking ugly or caused part lifetime, or even broken easily.. These weld lines troubleshooting occur usually around holes or at the material flow joint area in the injection molded part, some welding lines is very small, specially if the molded part made in fiber-glass material, must be …

Plastic Molded Parts | JAEGER Group

ALL-ROUNDER MADE OF PLASTIC Plas­tic Mold­ed Parts Plas­tic mold­ed parts insu­late, dec­o­rate, con­nect and stiff­en. Thanks to their spe­cif­ic prop­er­ties, they are increas­ing­ly replac­ing com­po­nents made of metal­lic mate­ri­als. Their advan­tages include high design free­dom, low spe­cif­ic weight, good cor­ro­sion resis­tance and high chem­i­cal ...

What are Injection Molding Defects and How to Control Them?

The following points should be considered to control short shot defects in injection-molded plastic parts. Increase wall thickness or provide ribs in the section where molten plastic is solidifying quickly. Selection of low viscous plastic with higher flowability. Increase injection plastic temperature and pressure.

Weld Line Defects in injection molding - Plastic Mold

Weld line defects in injection molding is a line or lines on the part surface that caused the part looking ugly or caused part lifetime, or even broken easily.. These weld lines troubleshooting occur usually around holes or at the material flow joint area in the injection molded part, some welding lines is very small, specially if the molded part made in fiber-glass material, must be …

Injection Molding And Plastic Part Design-Total FREE CONSULT

Designers avoid significant drafts when creating products since it alters the aesthetics and reduces the volume of the final product. Plastic moldings, on the other hand, often make use of drafts in order to prevent ejection problems and overly complex tooling designs. Specifying angles on ribs is very important.

Plastic Injection Molding Design Guide

Knit lines, also known as weld lines are areas in the molded part where two or more flow fronts converge. The area generally has lower strength than the other areas of the part. (See Fig. 11) The part design must take into account possible knit line locations and work to direct them away from higher stress areas.

What Is the Difference Between Knit and Meld Lines …

Aug 21, 2020·A meld line is defined as the remerging of two flow fronts after a feature within the part design splits the plastic flow. Visualize this as you’re getting onto the freeway after a long day at the office—we are all going the …

Plastic Molded Parts | JAEGER Group

ALL-ROUNDER MADE OF PLASTIC Plas­tic Mold­ed Parts Plas­tic mold­ed parts insu­late, dec­o­rate, con­nect and stiff­en. Thanks to their spe­cif­ic prop­er­ties, they are increas­ing­ly replac­ing com­po­nents made of metal­lic mate­ri­als. Their advan­tages include high design free­dom, low spe­cif­ic weight, good cor­ro­sion resis­tance and high chem­i­cal ...

By Design: Molded threads, Part 1 | plasticstoday

With 32 threads/in, the engagement is only .020 in/side. I once undertook a lens holder project that required molding a 21?8-inch-diameter acetal part with 40 threads/in. That thread provided an engagement of only .016 in/side. A ±.004-inch tolerance on both mating parts used up half of that engagement.

Knit Line Affect On Material Strength - Eng-Tips Forums

Aug 19, 2007·In a reasonable design a weld line will typically be 80% or better. Some variables are:- Temperature of the melt at the flow fronts where the two fronts meet. Pressure of the melt at the flow fronts where the two fronts meet. Effects of trapped gas and volatiles at the flow fronts where the two fronts meet.

TROUBLESHOOTING MOLDING PROBLEMS - IDI Composites

Ejector cracks are small, visible surface cracks on the cavity side surface of the molded part. These are often found on the opposite side of the part above an ejector pin. A crack located on the surface of the laminate that does not extend completely through the substrate. Probable Cause Material • Resin Reactivity

What Is the Difference Between Weld, Knit, and Meld Lines and …

Jul 07, 2020·In the plastic injection molding industry, we work with materials that are byproducts of oil refinement and molds made of metal casting, so our terminology is bound to be at least slightly confusing. Three terms that often get mixed up are weld, meld, and knit lines. Meld and knit lines are actually both different types of weld lines.

Weld Line: Its Causes, Defects and How to Avoid It

Weld line (also known as a knit line) is the line where two flow fronts meet when there is the inability of two or more flow fronts to “knit” together, or “weld,” during the molding process. These lines usually occur around holes or obstructions …

What Are Knit Lines In Injection Molding? - Rex Plastics

Knit lines, weld lines, mold lines, or flow lines in injection molding are faint lines that become visible on certain plastic parts. Weld lines may appear like seams or scratches, but that is not what they are. Wavy lines are another feature of weld lines. In injection molding, it is often important to maintain consistent color throughout the part.

What are Injection Molding Defects and How to Control Them?

The following points should be considered to control short shot defects in injection-molded plastic parts. Increase wall thickness or provide ribs in the section where molten plastic is solidifying quickly. Selection of low viscous plastic with higher flowability. Increase injection plastic temperature and pressure.

Scary Plastic Part Defects and How to Avoid Them

Short shot – An incomplete part due to lack of a filled mold. This problem is often attributed to a blockage or improper injection pressure. Warping – A part with a distorted shape can be due to a poor cooling system in the mold. When the plastic material is cooled unevenly, the result is a bowing effect. Most of the defects listed here can ...