Optimize processability of bioplastics

Published in Bioplastics Magazine 
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Working closely with sustainability partner, Dynisco, (Franklin, Massachusetts, USA,) Glycon Corp. (Tecumseh, Michigan, USA,) has incorporated Dynisco’s breakthrough technology in analytical instrumentation known as the Dynisco ViscoIndicator Online Rheometer into their screw design protocol. The ViscoIndicator provides continuous measurements of melt flow rates, apparent viscosity or intrinsic viscosity directly on the Glycon lab extruder. Dynisco aims to provide a window into the process for processors of all sizes in order to simplify rheology and improve quality and profitability. Glycon is maximizing this information by utilizing it in their screw design protocol to determine the best type of screw to run any bioplastic, composite, or blend of materials, as well as to determine the specific geometry and flight configuration of the feedscrew. Glycon has been designing feedscrews for the plastics processing industry for over 40 years. Whether the process is extrusion, injection molding or blow molding, the feedscrew design has a major effect on the quality and quantity of the end product being produced. As more bioplastics that have a favorable impact on the environment are introduced, key factors in their acceptability by manufacturers will be cost and processability. With accurate rheological data on the material, whether it be virgin material in pellet form, a blend of virgin or re-grind, a composite of plant based and recycled or even recovered ocean plastics, accurate rheological data, combined with Glycon’s experience and state-of-the-art instrumentation in their Innovation Lab, will provide the critical link to maximize output rates, provide a homogeneous mix and deliver a high quality melt on the new polymers being introduced.


Protocol for developing Bio-Screw® designs

1. Obtain and review material data sheets.

2. Analyze and determine material form and bulk density.

3. Establish processing goals and objectives. - desired output rate - discharge pressure - discharge melt temperature

4. Select processing conditions based on processing goals. - screw speeds - feeding rate- barrel temperatures

5. Select screw type and geometry. - conventionally flighted metering screw - barrier screw - distributive mix/melt screw - grooved or smooth feed - mixers required

6. Run material(s) monitoring: - temperature - pressure - apparent/intrinsic viscosity - melt flow rate - shear rate - viscosity at different shear rates - shear sensitivity

7. If more than one material is tested, run a comparative analysis.

8. Optimize performance: - adjust temperature profile - adjust head pressure - adjust screw speed - change/modify feedscrew

9. Prepare a detailed report on the test including: - number of trials - temperatures and screw speeds - horsepower - lb or kg/hr/rpm - torque - energy consumption - melt quality

10. Generate a screw design recommendation.


The Innovation Lab, equipped with Dynisco’s ViscoIndicator, gives Glycon state-of-the-art capability specifically targeted at sustainable materials and the circular economy. With live streaming available, material tests can be viewed around the globe in real time. 




Michigan State Rep. Bronna Kahle Tours Glycon


October 10, 2017 


The Plastics Industry Association (PLASTICS) invited Michigan State Rep. Bronna Kahle (R-57) to visit member company Glycon Corporation in Tecumseh on September 25. For over 40 years, Glycon has been manufacturing feed screws, barrels, non-return valves, tie bars and other melt stream solutions for injection molding, extrusion and blowmolding. Most recently, Glycon partnered with Dynisco to launch the Innovation Lab to test and analyze screw performance when processing bioplastic resins. They were excited to show Rep. Kahle their 40-man operation.

Rep. Kahle is a freshman member of the legislature and serves on the Health; Tax; Workforce and Talent Development; and Families, Children and Seniors committees. Throughout the tour she met new and familiar constituents all while learning about the role Glycon plays in the plastics industry supply chain.  She was particularly interested in understanding the challenges Glycon faces in hiring a skilled workforce for the future, how the state and county have been of assistance, and what the plastics industry of the future looks like.

Jeff Kuhman, Glycon president, had the following to say about the tour, “The employees of Glycon Corporation were enthusiastic about hosting Rep. Kahle and PLASTICS. This was an excellent opportunity for the Glycon team to voice their concerns and showcase their skills."

As the 60,000-strong plastics industry workforce continues to grow in the state of Michigan, we look forward to working with Rep. Kahle on policies that are supportive of our industry.

From Left: Rep. Bronna Kahle; Plant Manager Jeff Howard, Glycon President Jeff Kuhman

Rep. Kahle receives a first-hand-look at the precision technology involved in screw manufacturing


Source:  Plastic News,  October 3, 2017

Five Things Some Feed Screw Suppliers May Not Want You to Know

May 17, 2016

  1. Where was the screw manufactured?  There are numerous brokers with great looking web sites and search engine optimization that make a processor think they are dealing with a reputable feed screw design and manufacturing house.  In order to receive a quality product, processors should ask questions to include:   a) Country of origin - where the screw was manufactured b) Country of origin of the base steel of the screw (United States, Eastern Europe, China, etc.), c) Hard facing OEM or generic equivalent, d) Where the screw was coated i.e., chromed, carbide coated, nitride hardened, etc.   Brokers likely will not know the answers to many of these questions; however, screw manufacturers will know the answers to all of these questions.  Processors should be aware that not all material sources or coating vendors meet the same standards.
  2. How did the supplier arrive at the screw design they are providing?  Many screw designs may sound custom, but are, in fact, off the shelf versions.   A “one size fits all” mentality does not optimize for your specific process, materials, L/D, or other factors.  And what about custom mixing geometry such as distributive mixing melting designs?  Why aren’t those designs offered?  Only a few custom screw manufacturers will offer this alternative geometry because only a few understand how to design and implement it, and even less understand how to manufacture this geometry.
  3. Delivery – how can it be this fast?   If it’s available quickly, it’s probably a GP--General Purpose--design, also described as “Generally Poor” for many processes.  Something off the shelf may get you up and running sooner, but the processor must determine if getting something in 3 weeks or sooner that will process for 4 – 7 years is really the best value for the long term.
  4. Quality matters to consider?   Is the hard facing applied full flight width?   Many screws are “welded in the groove” with base material on the sides of the tips of the flights. That method, while cheaper to manufacture, will wear faster than a full flight width hard faced screw.  Other factors to consider include concentricity (think a circle turning inside a circle and how that might affect surging or side loading), hardness testing of hard facing (was the hard facing over diluted with base screw material during application resulting in relatively soft hard facing, for example), and straightening during the manufacturing process.  If a screw was ground straight, it may not be concentric.  These factors can all impact wear and processing.
  5. Price vs. value proposition?    The value proposition is always a consideration.  Price is what you pay, value is what you get.

By Mike Mieduch – Sales Manager at Glycon Corporation in Tecumseh Michigan.  Glycon Corporation has been designing and manufacturing feed screws for the plastics industry for 38 years.  Mike has been actively employed in the plastics industry for 41 years.

 Cracked Feed Throat Liner – Repair Considerations

 June 6, 2016

by Michael Mieduch

We’ve had many customers come to us with issues on feed throats. Liners that crack is just one of the common complaints from processors. When that happens, a host of process issues occur, including coolant in the plastic causing the processor to shut off the cooling fluid to the feed throat.  Then, with the intensive cooling shut off, the process must be slowed to compensate for the overheating and the shearing mechanism of the grooved feed.  A fast, low cost repair is desired, but none is typically available.

One of the reasons the liners crack is because most were designed with a clearance between it and the housing for easy removal for field replacement. The intent is to keep the water in with o-rings. The problem is the liner is brittle and unsupported. Expansion and contraction from thermal cycling will cause it to crack. Additionally, if the system is allowed to heat up without water flowing and then flooded with water, that shock could crack the liner. 

The Glycon engineering team identified this recurring issue as an opportunity to design a liner system that could 1) Provide a reduced opportunity for the liner assembly to crack in the first place and 2) Allow for faster low cost repair. Long lead time components can be manufactured 90% complete ahead of time and be available to finish and install into the existing housing in the case of a cracked liner.

In short, the Glycon liner assembly consists of a heat-treated, CPM 10V sleeve as the innermost surface for wear resistance. Outside of that, we design a piece that contains the water channels with a wall thickness such that it can take an internal pressure of 20,000 psi. The interference fit between this and the 10V sleeve provides support. We weld a jacket over the water channels so we aren’t relying on the fit between the liner assembly and the housing to keep the water in.

Glycon’s design has a light press between the new liner assembly and the housing allowing future removal and replacement without damage to the housing. Once the housing has been modified for the Glycon liner, downtime for replacement is reduced tremendously. With planned replacement, the liner assembly can be ordered in advance and be ready for the exchange with minimal turn-around time. Some processors can even do this in-house.

In conclusion, know that there are alternatives available to consider when the high wear and difficult to repair feed throat components require service.

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Glycon Corp.

912 Industrial Drive

Tecumseh, MI 49286



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