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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.

Documentation Takes Too Long…

I was in a discussion recently with a GM and he had this problem…

Manager
My technicians are not willing to take the time to document their changes. They claim it takes too long?

My Response
The issue here is not time, but education. If your employees are not taking time to document, it is likely that they do not fully understand the importance and benefits of good documentation. If they understand the ways it can simplify their job and improve their effectiveness, they would be more interested in compliance. Unfortunately, this is not a simple fix… it require the employees to not only understand the benefits, but also know what to do with the information they are given.
-Andy

Creating a Training Plan…

I was recently at a company who purchased some training a while back from a different provider under the guise of having a ‘resource’ for all their employees to use…

My Comments
Training is good, but it is critical that you tie the training to each job function through the use of a training plan. Without a structured training plan focused on job title you will not be able to make a change to your workforce. In general, your employees will not go and train unless there is a structure to show them what they are supposed to do when they train.
-Andy

The Best Way to Process…

I was recently at a molding facility during a training implementation was in need of some training due to a lack of fundamentals among the employees…

Company President
What is the best way to process, and why don’t we just have everybody process that way starting tomorrow?
My Response
I told her that there were ways that there are many ways to process, and there are a few methods which are far superior to others. Unfortunately without a strong background in processing knowledge your employees will have no reason to understand why this method is better.
Essentially, people who have been making a living molding a particular way do not just change their entire approach to processing because someone tells them it is better. You need to educate them on plastics, machinery, materials, processing, and tooling to ensure that they know why it is a better way.
Additional Thoughts
There are always steps which your employees can take to improve the process. As they see the success they will continue to employ more cost saving, and process improving techniques. This is one of the reasons why it can be easier to teach someone who has never processed that to teach someone who has processed for years.
-Andy

Melt Temperature and Density…

I received this excellent question last week…

Saeed
In one of your videos, you state that higher melt temperatures will increase part weight. To my understanding, a less viscous material is pumped in the cavity with a relative ease thus increasing the part weight. Could you please guide me as to whether or not a decrease in density negates the above?

My Response
You are correct that you will be injecting a less dense material in this scenario… but the higher melt temperature causes many things to occur, but the 2 major factors increasing the part weight and density are listed below:
1) There will be a higher amount of material flow and in-mold pressure during packing resulting in more material entering the mold during both 1st and 2nd stage.
2) A higher melt temperature promotes an increase in part shrinkage resulting in a higher overall part density.
Additional Thoughts
This question points out how complex the interactions between the mold, machine, material, and  injection molding process can become.
-Andy

Follow-Up on Increasing Injection Velocity…

I received an email from a blog reader about another benefit to increasing injection velocity…

Harry
Another reason we use a higher injection velocity in our facility is to increase the amount of packing that is possible.

My Comments
This is correct because of two reasons. First, the gate begins to freeze the moment the material enters the gate. The shorter time required to fill the mold allows more time for packing. The second reason is because the pressure loss within the mold cavity is decreased, allowing more packing pressure to reach the extremities of the mold during packing.
-Andy