Tag: FEA failure diagnosis

Creating a Virtual Plastics Injection Molding Window

By Bozilla
April 27, 2022

Since the inception of plastic injection molding, creating a robust injection molding process has always been a challenge As time has progressed, the design of plastic parts has become more detailed and intricate, the tolerances have become tighter and the boundaries of injection molding standards are being pushed to their limits The combination of each one of these factors is making it more and more difficult to create and maintain a robust molding process

Initially, it wasn’t difficult to design a basic injection molding window that would result in a robust molding process However, with the advent of increasingly demanding factors it has become more difficult to design a process molding window that is large enough to be robust and create consistently good parts As a matter of fact, not only is it difficult to create a wide process molding window, it’s nearly impossible to create a suitable molding window- Period We will discuss how and why it is necessary to first create a virtual injection molding window and how that data can be translated to the floor in order to have the best injection molding window possible

Let’s begin with understanding what a molding window (or process window) is Typically, a molding window is comprised of three major factors: Fill time (or fill speed), Mold Temperature and Melt Temperature Each of these factors has the greatest impact on the injection molding process

Graphs below will illustrate the impact of each

The influence of each factor:

  • Fill Time (fill speed): As fill speed decreases, the material moves into and through the cavity slowly which allows the cooling effects of the tool steel to have more time to influence and cool the temperature of the plastic resulting in a higher viscosity response and a greater pressure to fill the cavity Conversely, as the fill speed increases, the material will shear thin (the viscosity will decrease) significantly, but ultimately the plastic will resist filling the cavity and require a greater pressure to fill the cavity Somewhere between filling extremely slow and filling extremely fast is a sweet spot that requires low pressure to fill the cavity If plotted out in a graph, it will be a u-shaped curve where the lowest point is typically a good fill speed

molding window pressure

  • Mold Temperature: The mold temperature is highly influential with regards to having the material fill the cavity The thickness of the part relative to the flow length is an important relationship with regards to the impact of the mold
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Accuracy of Flow Simulation on Plastics Injection Molding machine

By Bozilla
March 15, 2022

I have recently been exposed to multiple articles and discussions regarding the implementation of flow simulation on injection molding machines This is an intriguing topic which I advocate Currently, this new combo method is proving difficult to line up the results from the analysis with the actual process on the injection molding machine In order to successfully utilize this capability on an injection molding machine, several factors must be understood

For those who have read my previous articles, you may appreciate that I strongly promote having the right person for the right job In other words, the simulation engineer must have a complete and comprehensive understanding of plastics in order to be able to properly simulate the plastics injection molding process

My suggestion is to always have a degreed Plastics Engineer with floor experience perform simulations on plastic parts The reason for this advocation is to ensure that the simulation engineer virtually takes on the role of the process engineer This makes certain that the simulation will properly emulate the injection molding machine process on the part being molded Unfortunately, this is not always the case and the articles I have recently read do not touch on this very important factor A virtual simulation cannot simply be executed, have the results taken to the floor, input into the injection molding machine and expect the molded part to perfectly match the simulation results It’s not that easy due to many variables which must be considered

Plastics injection molding optimization

For example, the simulation engineer (with the proper degree and experience) will understand the limitations and boundaries of the intended injection molding machine for that particular simulated part It is not always necessary to know every specification of the machine and to input that specific data into the simulation Most machines have a wide variation of capabilities that the simulation engineer will take into consideration The simulation will then be executed with all of the necessary variables factored in for the injection molding machine, thus maintaining a high degree of accuracy between the simulation and the floor

The difficult task is discovering those unintended variables that affect the process on the floor, eg material batch changes, colorant issues in the polymer, tool temperature variations that the press cannot record, physical changes within the tool such as polymer sticking to action within the tool, cold gates not opening and flowing when desired, cosmetic issues at the gate or

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Failure Diagnosis-Product & Process

By Bozilla
August 12, 2021

Bozilla Corporation’s core business is performing CAE analyses, specifically mold flow analyses, on products to optimize both design and process Our procedures and standards set a benchmark to create the highest degree of part quality with the least amount of difficulty and waste

Because many companies have not used FEA, they are turning to the injection molding specialists at Bozilla Corp with issues relating to part failure or processing problems Fortunately, we are solving many of them with Failure Diagnosis

What exactly is Failure Diagnosis?

Failure Diagnosis is the process of identifying why a product or process isn’t performing properly

The injection molding professionals at Bozilla Corporation have cultivated and executed proven techniques to execute this vital task and resolve our customers’ concerns on all levels

This type of diagnosis requires calculated procedures and thorough knowledge in:

✔ CAE Analysis

✔ Root Cause Analysis

✔ Experience with similar products/issues

✔ Indepth knowledge of polymers

If you are experiencing problems with a product in the field or with its process, we will implement our procedures to assist in solving these issues

 Some examples may include:

➤ Start up times for a tool are taking longer than expected, the process is difficult to stabilize, or the start up time on the same tool varies from machine to machine

➤ The process has variation and too many bad parts are being produced

➤ The parts seem to be fine but are failing in the field which causes customer dissatisfaction and more work/costs for you

As an added bonus, the Failure Diagnosis procedures can further lean your process and potentially save you money

Bozilla Corporation has worked extensively with companies to resolve their injection molding performance issues Contact us today and find out how we can help diagnosis any issues you may be having with your injection molding product and/or process and get you back on track!



We Know Injection Molding! Plastics Engineering, Consulting, Optimization, Failure Diagnosis, Training

About the author

Chris Czeczuga is a Plastics Engineer, Injection molding expert, Military Veteran and the President of Bozilla Corporation He has proven success with many OEM’s Tier 1’s, Tier 2’s, Tool Shops, Molding shops, Part Designers, Processors and Fortune 500 companies throughout the injection molding industry A graduate from UMass Lowell, he is Expert Certified with Autodesk, has 20 years of field experience, intimate knowledge of injection molding part, tool and feed system design Bozilla Corporation’s success is built on providing the highest level of injection

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