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This informative blog allows plastics professionals to discuss plastics training and technology. Brought to you by Routsis Training: the plastic industry's premiere training provider.

More about Traditional Molding…

I was recently asked this question at a classroom/hands-on training session…

Participant
Most of my co-workers use traditional molding, why should I convince them to change?

note: traditional molding refers to the method of filling the mold cavity all the way during 1st stage fill. This method is often referred to as traditional because it was the preferred method of processing for the traditional pressure-controlled molding machines which used to dominate the molding industry 20+ years ago.
My Response
In today’s molding industry, the profit margins and tolerances for most products are very tight.  The traditional method does not provide the processing flexibility and compensation for variation necessary to succeed in the long term. An inability to change will cause inefficiencies which will become unacceptable at some time in the future resulting in either job loss or eventual company failure due to an inability to compete.
Additional Thoughts
In order to change the behavior of your technicians, you need to implement a structured training program which teaches and reinforces the right molding practices over an extended period of time. 
-Andy

Training for Blow Molding…

I was recently asked this question by a Training Manager…

Manager
There are few training options specifically for continuous blow molding. What else can I do to help my technicians?

My Response
Most blow molding technicians have to perform a large number of roles from troubleshooting to maintenance. For this reason, a continuous blow molding technician would benefit from a wide array of training including hydraulics, mathematics, blueprint reading, plastics materials, troubleshooting, extrusion, as well as fundamental blow molding training.
Additional Thoughts
Always look at the diversity of any particular job position when devising a training plan for your employees.
-Andy

Who Needs Hands-On Training…?

During a recent on-site visit, I was asked this question…

Trainer
Does everyone need to go through hands-on training?
My Response
Structured and customized training can provide an extensive amount of important information… but it does not replace hands-on experience. For this reason, anyone working on the production floor should be involved with some degree of focused, hands-on, instruction.
Training should be used to teach the concepts followed up by focused hands-on instruction to relate the training to the workplace.
Additional Thoughts
Those who do not work on the production floor, such as managers, will also benefit from the experience… though I understand it is very difficult to get such people to participate.
-Andy

Is Profiling Better…?

I recently received this question last week during a training session…

Student
If I make a good part without injection profiling, but later, another employee later uses injection profiling to make the same part should that be the new standard?
My Response
If you can make acceptable parts with one injection velocity, then you should continue using one injection velocity. Each time you introduce another injection velocity to your profile, you increase the overall complexity of the system. This creates an addition point in the process where variability can be introduced as well as more potential for process tampering.
Additional Thoughts
The goal of a processor is to establish a process using a straightforward systematic approach to setting each process parameter. If one profile can do the job correctly, there is no need to add a second velocity since the additional complexity can not be easily justified.
-Andy

Is it 90 or 95% Short…?

I often see many people getting hung up on the specific percentage fill for first stage short shots…

Student
In a 4 cavity mold, I usually have to make the part 90% full to create a short shot in all cavities. Is that OK, or does it have to be exactly 95% full?
My Response
It is more important to have a short shot in each cavity than it is to have the mold 95% full. Personally, I am less concerned about the percentage being 90 or 95% than I am about the cavities being short shot. If you have a short shot in each cavity, then you can properly compensate for variation during fill. If you are already full during 1st stage, then you have no buffer for variation, and are likely to encounter shorts and flash over the course of your run.
Additional Thoughts
For more about this and related topics, please feel free to read the following:
-Andy