July 2007 Edition

CAD/CAM

Alternatives to ‘That Old Black Magic’

Visualization and design software removed the “black magic” factor from mold design for the customers of an Illinois company

Injection and insert molding had a high “black magic” factor for some of DMC Mold & Tool Corp., Cary, IL, customers. Determining how material entered the mold through runners seemed more art than science. Reducing the size and number of runners was often a guess based on experience. But, that changed for DMC when it found the right visualization software.

Before any metal is cut for molds, DMC Mold & Tool Corp. first models the mold using VISI-Flow software to verify the design to prevent the need for remilling the mold to correct deficiencies

DMC designs and builds molds for the plastic injection and insert molding industry. The company specializes in turnkey project solutions.

The firm’s core competency is in the part design phase for manufacturability, where customer and supplier communication is most important. The design and manufacturing team at DMC uses its experience to create solutions which require complex tolerance schemes, insert interchangeability, and molding considerations.

Custom plastic molders are the company’s primary customers.

The biggest challenges for designing and building molds are maintaining customer requirements, such as adhering to their quoted cycle time along with reducing runner volume, while continuing to produce quality products, according to Dustin Carlson, DMC president and owner.

A long-time user of Vero International, Wixom, MI, VISI-Series modeling software, DMC supplemented the software suite with VISI-Flow, a mold design application.

 

Model Analysis

Using VISI-Series, DMC creates a 3D model of molds to analyze and determine whether or not the molds will perform to expectations.

“Prior to VISI-Flow we relied on the customer’s knowledge about where to locate gates and runners, as well as gate and runner sizing,” Carlson said. “The customer established runner size and location based on their expectations. They hoped to minimize scrap and maximize quality part potential.”

Accurate design of injection-molded parts using visualization and design software can reduce the amount of waste in runners [the channels in which the material is injected] and keep parts profitable

In the injection molding process, a gate is the location at which the material enters the mold. Runners are large-diameter channels through which material flows, usually around the edges of the part or along straight lines.

“For many projects, we witnessed our customers struggling to establish mold specifications. Each customer had a go-to person upon whom they relied to decide the best outcome for the mold design,” Carlson said.

“We watched as customers tried to maintain quality, cycle time, and reduce production scrap. Projects suffered because of this traditional method. Relying on one person’s expertise is not the way to profit in this economy.”

DMC took the guess work out of mold design with VISI-Flow.

“With the software, we can demonstrate the benefits or drawbacks to customer design of runner and gate locations,” Carlson said.

More than Just Pretty Pictures

The software provides a full re-creation of a design. The software also predicts cycle time. Mold fill accuracy includes a timing element. The application’s estimations and visualizations help customers see if they are meeting required cycle times.

“Traditional methods were expensive and time-consuming,” Carlson said. “Money and time were wasted making mold changes once a tool was built. VISI-Flow gives us the ability to make adjustments to the design before the tool is built.”

DMC received an order for an insert mold from an automotive products supplier. An insert mold involves a stamped metal insert placed in a mold where plastic is molded around it. The mold had two small plastic sections.

“VISI-Flow provided the information we needed to determine runner placement,” Carlson said. “We reduced runner size and weight so there was an 18 percent savings in scrap.”

In another project, the company was contracted to build a replacement for an existing mold that did not meet customer capacity requirements.

“We started the project knowing the mold did not fill correctly. Using VISI-Flow, we researched how to improve runners, gates, and cooling,” Carlson said. “We discovered a molded-in stress causing a fracture in the part. The custom molder had to adjust its cycle time to a period longer than quoted.

Part of DMC Mold & Tool’s shop where molds are created

“We showed the customer where the molded-in stress point was located, then revised the gate placements and sizes using the VISI-Flow results.”

Creating gate locations, gate size, runner locations, and runner sizes are the biggest strengths of VISI-Flow, according to Carlson.

“The software is powerful and fast,” Carlson said. “It provides customers with an in-depth visualization of the mold design. If we make a change, the customer can see the results of that change.”

Quote Assistance

Carlson said VISI-Flow is not only an engineering tool, it also assists in job quotes.

“In this market, we need the right tools to satisfy customers’ needs. We can pass along to our customers the benefits we realize.”

Learning the capabilities of the software package is a continuous process for DMC.

“We’re only using about 50 percent of the software’s capabilities,” Carlson said. “VISI-Flow is so powerful that it’s a constant learning experience. With VISI-Flow, we were profitable from the start. Due to our experience with the VISI-Series software, we topped the VISI-Flow learning curve in about four weeks.”

Carlson said he appreciates Vero’s support of its VISI-Series and VISI-Flow products through online documentation and tutorials. Vero and its distributor provide 24/7 telephone support. Carlson said hotline support is responsive.

Vero International www.rsleads.com/707mn-207

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