10 Terms You Need To Know If You Want To Work As An Injection Molding Technician

13 September 2016
 Categories: Industrial & Manufacturing, Articles


Injection-molding technician jobs are a great choice for people looking to get into a trade career, but who don't have much experience in the field. It's the type of job you can learn as you go, and a college degree or professional license isn't required. As an injection-molding technician, you can expect to earn an annual salary of between $27,094 and $55,209. To give yourself a boost above other applicants in this field, you should familiarize yourself with the industry lingo. Knowing industry terminology will give you a better chance at landing the job than other applicants who also have no experience in this field. Here is a list of 10 terms that you should know if you want to work as an injection molding technician.

1. Flash

This refers to the extra plastic that hangs from the shut-off locations or along the parting line in the mold.

2. Burn

This is the term used to describe when a burn mark is made inside the mold. The burn mark is a patch of discoloration or distortion where the surface of the plastic has been destroyed. It is an indication that the temperature inside the mold has exceeded the flash point of the plastic. The higher the temperature is, the more destruction you'll see on the surface of the plastic.

3. Ejector Confirmation Switch

This is a switch that detects when the ejector plate doesn't fully return to the home position. It's a safety feature that prevents mold damage.

4. Knit Line

Also called a weld line, this is a mark left of a molded piece of plastic where 2 flow fronts meet during the molding process. Think of it as a seam where 2 pieces of plastic are fused together.

5. Nozzle Tip (Removable)

Molding technicians use molding machines to create their molds. There are many different types of nozzle tips used on these machines, and the technician must choose the correct one for the task at hand. Specifically, the removable nozzle tip is used to seal off high injection pressures and the mold sprue. The sprue is the channel where the plastic is poured into the mold.

6. Guide Pins

Also called leader pins, these small devices ensure the core and cavity of the mold are properly aligned at all times. This is especially important while the mold closes, because that is when the risk of misalignment is greatest.

7. Jetting

This happens when an undersized gate is used and a strong and fast-moving flow of resin oozes into a bigger or thicker mold section. This is as opposed to a constant but not turbulent flow of resin that progresses radially from a gate to the extremities of the mold cavity, which is called a laminar flow. It is ideal to have a laminar flow, not a jetting flow.

8. Short Shot

This is the term used for a molded part that was made when the mold was not completely filled with resin.

9. Plasticize

This is the word used to describe the action of softening a material to make it moldable or plastic by applying heat or using a plasticizer. A plasticizer is an additive or dispersant that will increase the plasticity or fluidity of a material.

10. Purging

This is when the technician forces a purge compound through the molding machine to remove the exiting material or color in order to start a new production job with new materials or colors. Alternately, the new color or material can also be forced through the machine in order to remove the prior material. When the new material is coming through cleanly, the next production job can begin.

Once you are familiar with these terms, you'll be able to communicate better with project managers, engineers, and other mold technicians on the job. It also proves to the interviewer that you are committed to learning the job and want to be successful in the field. If you have any questions, contact a company that recruits injection molders, such as Molding Business Services.


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