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Mack Honored as Supplier to 2012 Medical Design Excellence Award Winner

June 5, 2012 by Julie Horst Leave a Comment

Mack Molding Co. has been awarded as a supplier to the SnapPath 1000, the Silver Winner in the In Vitro Diagnostics category of the 2012 Medical Design Excellence Awards (MDEA) competition. The MDEA winning products, and their suppliers, were announced at a presentation ceremony held last week in Philadelphia in conjunction with the eastern Medical Design & Manufacturing Show.

Manufactured by BioMarker Strategies (Baltimore, Md.), the SnapPath platform is an automated live tumor cell-processing instrument that helps medical oncologists determine the best treatment options for individual cancer patients.

Mack injection molds the disposable cartridge kit for the device out of polypropylene resin for reagent compatibility. The fully self-contained disposable cartridge houses all of the reagents and pipette tips required for single sample processing.

“Polypropylene has a higher shrink rate than most resins, which made consistent wall thickness critical in this part’s design,” says Randy Pell, Mack senior staff design engineer. “We worked extensively with the designer (HS Design, Gladstone, N.J.) on design-for-manufacturability issues to ensure correct wall thicknesses and flow pattern, to build a robust tool, and generally, to improve overall moldability. The base housing cartridge is the most difficult of the four parts to mold.”

MDEA-winning products excel in the areas of product innovation, design and engineering achievement, end-user benefit, and cost-effectiveness in manufacturing and healthcare delivery. The winning entries were chosen by an impartial, multidisciplinary panel of third-party jurors with expertise in biomedical engineering, clinical practice, diagnostics, human factors, industrial design, manufacturing, and medicine.

“We are extremely proud to play a role in the manufacture of this product,” says Jeff Somple, president of Mack Molding’s Northern Operations. “This award program is the most prestigious in the industry for medical device design and innovation, so we are very honored to be a part of it.”

For more information on the Medical Design Excellence Awards, visit www.MDEAwards.com, or email mdea@ubm.com.

About Mack Molding
Mack Molding is a leading custom plastics molder and supplier of contract manufacturing services. Mack specializes in plastics design, prototyping, molding, sheet metal fabrication, full-service machining and medical device manufacturing. Founded in 1920, Mack is a privately owned business that operates 10 facilities throughout the world. Don Kendall is president and CEO. For more information, go to www.mack.com.

Use Gas-assist Molding to Consolidate Parts

July 12, 2009 by Julie Horst Leave a Comment

Gas-assist injection molding was developed several years ago to overcome the limitations of conventional injection molding. It has gradually moved into several industries, offering new technical and creative possibilities to design engineers. Michael Hansen, PhD, senior technical development engineer, talks here about the role of gas-assist technology in consolidating multiple parts into a single component.

Gas-assist injection molding is especially appropriate for three main categories of plastic molded parts:

Tube- or rod-shaped parts
Large, cover-shaped structural parts
Complex parts with both thin and thick sections, typically resulting from part integration.

Cross-section, gas-assist injection molded keyboard surround A medical device OEM approached us with a part design that clearly fell into the last category. The customer had already designed the part, which is a keyboard surround for an ultrasound system. Their goals were to integrate several different parts into a single, load-bearing component, and cut costs to improve their competitive position. It was our job to determine how to mold the new design as effectively and efficiently as possible. Here’s what we were looking at.

Wall thickness illustration Originally, this keyboard surround was made of nearly a dozen distinct parts. The new design integrated everything into one plastic part measuring 29″L x 21″W. The result was a thick-walled injection-molded part with molded-in handles. The main wall thickness was 0.6″. It also featured built-in thick-wall part details and a tubular detail. The thick tubular sections, close to 2.0″ in some areas, were primarily located on the perimeter of the part, making it a complex application from a processing perspective.

Two important rules
If you have a series of parts, whether they differ in thickness or size, and they have to be assembled using inserts, screws or other types of connectors, there is really no limitation to what you can combine using gas-assist injection molding as long as you follow the rules for filling the part and gassing it out.

Rule #1: When filling the part, you can only push the resin x number of millimeters in length per millimeter of wall thickness. In this instance, using PC/ABS resin, we could push the resin 100-120 millimeters in length for each millimeter of wall thickness.

t is very important to understand and appropriately design the filling pattern before injecting the nitrogen gas. The design should be adapted according to the planned or existing gas channel network. The gas channel layout depends on the size, shape, course and length of the gas channels. It also depends on the location of the injection point, part geometry and the needle position for gassing. You can obtain this information through iterative testing or by using mold-filling simulation programs. Here, the processing parameters, as well as rheological and thermal behavior of the polymer, are very important.

>Rule #2: Maintain uniform wall thickness, aided by the nitrogen gas, throughout the whole part. If you allow too much wall thickness, warpage can occur, as well as longer cycle times, thus excessive cost.

As mentioned above, you have to achieve a certain filling pattern. In this case, all the thick sections are arranged on the perimeter of the part. So we had to fill the part 100 percent with the polymer melt, and then allow the gas to hollow out the thick sections and help compensate for shrinkage. In the end, we used a single gate for introducing the resin, six gas pins, and two overspill cavities.

Now that I have emphasized the rules, I will also admit that they can be bent slightly if you go from an amorphous resin, like PC/ABS, to a semi-crystalline resin, like nylon. Semi-crystalline resins will usually set up at a higher temperature. As an example, if you make a thick part out of a nylon resin, you can achieve a thicker handle. There is a direct correlation between resin and wall thickness, so the resin family you choose will determine how thick you can go.

If you’d like to learn more about gas-assist injection molding, contact Michael Hansen, PhD, senior technical development engineer, Mack Molding, michael.hansen@mack.com.

AC Cover Design Wins Big

May 19, 2008 by Julie Horst Leave a Comment

Up to $1.4MM Annual Savings, SPI Award
Trane, the air-conditioning systems and services business of American Standard Companies, works to improve productivity on existing products by six percent every year. Because of quality issues with the cosmetic top cap for its top-of-the-line residential air conditioner, the top became an ideal candidate.

“We knew we couldn’t simply expect our supplier to take six percent out of the price of the product while still maintaining the quality,” says Bob Kiermaier, Trane strategic commodity manager. “To accomplish our goals, we needed a collaborative environment where we could work together to change processes.”

The Challenge
In addition to cutting costs, the Trane redesign team wanted to streamline manufacturing by consolidating the original multi-piece assembly into a single part. Formerly, the cover was built of five separate parts, requiring three molds to produce each part. The parts then had to be glued, often leading to loose louvers that contributed to a number of problems. “You can imagine the productivity gains that were possible just through mold reduction alone,” says Ken Kincaid, Mack technical engineering manager.

The Solution
The eventual new top cap design involved design, processing and assembly changes. The part is injection molded at Mack’s Inman, S.C., plant. Injection molding produces fast molding cycles for a high volume part with cosmetic requirements. External gas
is also used, however, to produce the cavity texture and improve part ejection from the tool. External gas-assist molding also lowers the injection pressure required to fill the part, reducing press size requirements along with costs.

The material choice for the new design is a UV stabilized polycarbonate resin for strength, impact, long-term aging, cosmetics and the color stability required for an outdoor application.

The most impressive technical aspect of the project is reflected in the part’s geometry changes and how they work with the tool design. “Slide lines in the tool combine with style lines on the side of the part, eliminating any interruption in texture appearance,” explains Kincaid. “And because the louvers are now integral to the part, its structural aspects and strength properties are improved. Most of the core side ribs that were previously needed have been eliminated, as well as the associated sink and flow disruptions.”

“The absence of any read-through on the top surface results in a better overall appearance,” adds Trane Plastics Engineer Richard Jameson. “The Xli badge can only be installed in one location, and there is better screw-hole alignment for assembly and increased structural integrity.”

The bottom line? The redesign yielded a top cap that will cost up to $1.4 million less per year to produce, according to Kiermaier. It also won the Building & Construction category of the Society of the Plastics Industry’s annual plastics design competition.

“Collaborating on a project like this is an effective strategy to use with a major supplier,” says Kiermaier. “Working closely with the supplier and sharing the cost benefits is always going to work better than a unilateral dictate.”

The Xli top redesign team included staff members from Trane Residential Systems, Mack Molding, Advanced Innovative Design and Delta Mold.

Contact: Jack Katilius, Mack Business Unit Director
jkatilius@mackmolding.com

Ken Kincaid, Mack Technical Engineering Mgr.
kkincaid@mackmolding.com

About Trane
Trane is a leading global provider of indoor comfort systems and comprehensive facility solutions. Its offerings include energy efficient heating, ventilating and air conditioning systems, service and part support, advanced building controls and financing solutions. For more information, visit www.trane.com.

AC Cover Wins Award for Trane, Mack Molding

May 28, 2007 by Mack News Leave a Comment

FOR IMMEDIATE RELEASE

MEMPHIS, Tenn. – A cosmetic top cap for Trane’s top-of-the-line residential air conditioner won the Building & Construction category at the Society of the Plastics Industry’s annual plastics design competition held this spring. Newly named the Alliance of Plastics Processors Conference & New Product Design Competition, the event attracted 31 complex entries representing multiple processes and materials.

Trane’s AC cover was no exception. Molded at Mack Molding’s facility in Inman, S.C., the new top cap design is injection molded, which produces fast molding cycles for a high volume part with cosmetic requirements. External gas is used for cavity texture replication and improved part ejection. External gas also lowers the injection pressure needed to fill the part, reducing press size requirements as well as costs.

The cover is molded of UV stabilized polycarbonate resin for strength, impact, long-term aging, cosmetics, and the color stability required for an outdoor application.

The new cover design – a collaborative effort among Trane, Mack Molding, Advanced Innovative Design and Delta Mold – is now one part produced in one mold with no required assembly. Formerly, the cover was built of five separate parts that had to be glued, and three molds were needed to produce each part. “You can imagine the productivity gains we’ve realized through mold reduction alone,” says Ken Kincaid, Mack technical engineering manager.

The most impressive technical aspect of the project is reflected in the part’s geometry changes and how they work with the tool design. “Slide lines in the tool combine with style lines on the side of the part, eliminating any interruption in texture appearance,” explains Kincaid. “And because the louvers are now integral to the part, its structural aspects and strength properties are improved, eliminating most of the core side ribs that were previously needed and the associated sink and flow disruptions.”

“This project is an excellent example of part and tool design working in concert to simplify design and consolidate parts, while meeting all critical aesthetic and functional criteria,” says Mack Business Development Director Brian Sumpter.

About Mack Molding
Mack Molding is a leading custom plastics molder and supplier of contract manufacturing services. Mack specializes in plastics design, prototyping, molding, sheet metal fabrication, and medical device manufacturing. The company operates seven facilities throughout the eastern United States. Founded in 1920, Mack is a privately owned business with over 1800 employees in North America. For further information, call 802-375-2511 or visit Mack on the web at www.mack.com.

About Trane
Trane, the air conditioning systems and services business of American Standard Companies, is a leading global provider of indoor comfort systems and comprehensive facility solutions. Its offerings include energy efficient heating, ventilating and air conditioning systems, service and parts support, advanced building controls and financing solutions. In 2006, Trane contributed $6.8 billion to American Standard’s total sales of $11.2 billion. For more information, visit the Trane web site at www.trane.com.

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Mack Honored as Supplier to 2012 Medical Design Excellence Award Winner

AC Cover Wins Award for Trane, Mack Molding

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