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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.

Approaching Training With Your Employees…

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

Kevin
How do I discuss training with my employees in a manner which makes them accepting?

My Response
When discussing employee training, it is critical to focus on how it will affect the employees. For example, if operators are not involved in the training initiative during the first couple months, let them know when they will be trained, and who will be taking the training first.
Explain a few of he specifics such as, how many hours a week or month they will train, the types of information they will learn, how the training will benefit the company as well as how it will benefit the employee.

With any initiative, employees will look to management for honesty and their commitment to maintaining the program. Keep the program transparent and track the progress visibly so everyone can see the program actually being used.
Many companies start a new program and then let it fall by the side when it looses visibility. Always update the employees on the progress of any company initiative.
Additional Thoughts
Don’t be afraid to make this process fun. Banners, luncheons, gifts, and announcements are great ways to inform your employees.
-Andy

Getting a Spotting Press…

I received this question over the weekend…
Jason
A friend of mine recommended I get a spotting press for the molding department. What are their uses and should I consider getting one?
My Response
A spotting press is great for checking the parting line. This is a large hydraulic press specifically designed to open and close the mold. 
Spotting fluid is placed on the parting line and the mold is closed under pressure using the press. Areas where the spotting fluid transferred from one half to the other are areas where the parting line is shutting off successfully. A parting line mismatch exists in areas where the spotting fluid does not transfer from one side to the other.
I recommend that any molder either have a spotting press, or access to a spotting press. If you have a toolmaking department, it is a necessary investment. 
Additional Thoughts
If you are a small molder, or have a small tooling department just for repairs, then it might be a price advantage to bring the tool to a local tool shop and borrow their press (this will also expose you to their expertise in evaluating the results).
-Andy

Calculating Apparent Shear Rate…

I received this question form a colleague through Linked-In last week…

Colleague
How do I calculate the flow rate of the polymer from the known gate cross-section area?
My Response
The formula for the appearant shear rate through a rectangular gate is as follows:
Appearant Shear Rate = (6 x Q) / (W x H x H)
Q = polymer flow rate
W = gate width
H = gate thickness
Additional Thoughts
As long as the flow rate and gate dimensions are in the same units (mm, cm, or in) they will cancel out and you will receive a a resultant in the units of reciprocal seconds which will represent the rate of shear.
-Andy

Problems with Drool…

I received this question the other day…

AS
We are having problems with material leakage between the nozzle and the sprue. Is there some way we can adjust this?

Note: after some further questioning, it was determined that sprue break was not being used, the nozzle position has been aligned, and the diameter and radius are correct.
My Response
Basically, you need to increase the contact force between the nozzle and the sprue bushing. This will often relate to the carriage forward force or position.
-Andy

Intensification Ratios for Electric Molding Machines…

I received this question on our online chat feature earlier today…

Agustin
Can you please give me the IR (intensification ratio) for an electric molding machine?
My Response
Electric molding machines do not have intensification ratios because they lack hydraulic pressure. Your machine should be configured to provide the actual injection pressure.
Basically, an electric molding machine measures the injection force using a conversion from the torque applied during injection. This conversion provides the actual injection pressure on the control panel. 
Additional Thoughts
he only time you may need a conversion is if the screw and barrel were replaced, and the machine was not re-programmed to accomodate.
-Andy