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Plant Tour: Big molds make for big business

Niches come in all sizes, and for one Midwestern mold manufacturer, the bigger, the better when it comes to molds.

Clare Goldsberry

March 9, 2011

9 Min Read
Plant Tour: Big molds make for big business

Niches come in all sizes, and for one Midwestern mold manufacturer, the bigger, the better when it comes to molds.

When IMM walked onto Triangle Tool Corp.’s production floor, it looked very similar to others with one large exception: Everything is very big. The company’s 173,000-ft2 facility contains some of the largest CNC machine tools in North America, giving Triangle Tool the ability to manufacture extremely large molds. The most recent facility expansion was completed in July 2009 and added 18,000 ft2.

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Triangle Tool’s 173,000-ft2 manufacturing facility sits on 18 acres of land on the northwest side of Milwaukee.


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Technical sales engineer Dan Gouge (right) discusses customer-critical requirements on a mold with process technician Jeff Schneider.


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One of Triangle Tool’s fastest-growing business segments is the material handling market, and pallets are in big demand.


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The Pragma five-axis machining center from FPT is one of two that Triangle Tool operates, and is a workhorse for building large molds.


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The multiaction molds for dishwasher tubs contain actions within actions and are built so the entire outside of the tool lifts away.


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Triangle’s Kuraki Machine Scan is one of 15 large boring bars that the toolmaker operates, and is seen here adding vent channels to multiple single cavity tools.


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This FPT machining center is creating an H-13 mold insert for a battery case.


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These three FPT stinger machines perform much of the hard-cutting for the multicavity molds the company produces for Rubbermaid

The Milwaukee, WI-based company was founded in 1963. Roy Luther purchased it 20 years later, and in 1985 he built a new facility on 18 acres where the company currently operates. Today, Triangle Tool is ranked as the fourth-largest mold manufacturing company in North America, according to the Plastics News moldmakers survey, and is one of just a handful of mold manufacturers with the knowledge and structural capabilities to design and build injection molds of the size, complexity, and diversity that the company offers.  

Victor Baez, technical sales manager for Triangle, says the company has always built larger molds. “When Triangle moved into this facility, we installed a 1000-ton sample press, followed by a 3000-ton press,” which sealed Luther’s commitment to stay in the large-mold arena, he explains. “Our niche is large, highly engineered molds, and we do these better than anyone else in the world.”

With the commitment to molds of this size comes a number of challenges, including the capital investment needed for equipment that can handle molds weighing more than 100 tons. The recent addition included a 100-ton crane. “Just the handling of these extremely large molds is tedious, but it’s made easier because of the number of cranes—20-plus—that we have,” says Baez.

Getting the layout
While walking around the facility, we notice that there are rail tracks running through the shop to accommodate large carts that can be easily pushed manually. These rail tracks span bay-to-bay to allow easy access to all departments of the production facility.

While many moldmaking companies operate as job shops, Triangle Tool is truly a mold manufacturer. The company is very departmentalized, so rather than a mold moving from machine to machine under the watchful eye of a single moldmaker as in many job shops, the molds move from department to department, which makes scheduling a critical function.

Separate departments exist for lathe work and turning. Triangle has 12 mold polishers—six on days and six on the night shift. A core team of toolmakers assembles the molds and sends them to be sampled and qualified in one of the company’s large-tonnage presses.

Triangle samples three to four molds a day. On the day IMM was there, employees were sampling a large stack mold in the 3000-ton press for a major supplier of plastic pallets. The 3000-ton press has a 540-oz shot size that can produce parts greater than 30 lb. In addition to the 3000-ton press, 
Triangle Tool has two 1000-ton injection molding machines, including a wide-platen 165-oz press and a Husky Hylectric with a 249-oz shot.

Broad customer base
Triangle serves a wide range of customers in diverse industries. One market segment that has been a big growth business for the company is plastic pallets and returnable packaging containers (RPCs). “With everyone going green, there are a lot of new designs for knockdown-style containers for easy return shipping. It’s a very stable industry that’s really sparked a lot of interest and growth in North America,” notes Dan Gougé, Triangle Tool’s technical sales engineer. “We’ve been involved in this industry for a long time and bring extensive expertise that few have.”

Triangle also makes molds for 95-gal recycle carts, consumer storage products, and large appliance, heavy truck, and agricultural equipment components. “We’re really a nonautomotive mold producer,” says Gougé.

Specialty machining, mold engineering
Contract specialty machining services for a wide variety of companies that require extremely large machined parts help Triangle optimize machine tool capacity. “There are only so many spindle hours required for moldmaking,” Baez says, “and with the people and equipment we have, we’re in a unique position to take on large-part machining, which also allows us to maximize our capabilities.”

During IMM’s visit, Triangle Tool was machining missile ballasts for U.S. Navy Zumwalt class destroyers in a large Mecof bridge-style vertical machining center. “We have the capacity to do this work and we’ve blended it quite well with the moldmaking,” says Baez. “However, there are still some areas where we’re restricted because of the need for even larger-sized machine tools.”

In October of this year, the company will take delivery of a five-axis horizontal machining center with a 65-ft travel bed. “We’ll incrementally go where we need to go to allow our specialty machining business to grow without detracting from moldmaking,” Baez says. “We will not interfere with our injection moldmaking operations—that trumps everything.”

Engineering is key to building extremely large molds. Triangle has 10 engineers for design and programming of the molds. The biggest challenge is the ability to design and build molds with multiple actions, taking into account the tremendous weights these actions have to carry. For example, just one slide in a dishwasher mold can weigh 30,000 lb.  When a dishwasher mold opens up, there are four large cavity “fall-aways,” and on the core side, two large A-frame lifters. Within those actions are also a series of hydraulic actions.

“This is where our Asian competitors fall short,” Baez says. “A customer may take a set of prints overseas, but a mold is more than steel. They can’t engineer the clearance and fit and weight-bearing aspects of a mold this size. Our molds are a marvel to watch and truly a unique feat of our engineering.”

Big molds for big parts
Besides conventional mold steels, Triangle Tool uses a lot of MoldMax (copper alloys from Brush Wellman) and aluminum. Gougé notes that the industry is turning more to aluminum for large molds. “When customers need cooling but also the strength of MoldMax, we go that route. But when we can, we use aluminum in areas that are not on shutoffs or slide features,” he says. “Cooling properties are better and it doesn’t cost as much as MoldMax. Cycle time is critical, especially in very large parts that have thick, nonuniform wall sections that are difficult to cool, so the use of MoldMax and aluminum is critical to getting the heat out of these areas.”

Because of the size of the parts, many molds Triangle Tool makes are single cavity, so it receives orders for multiple molds for producing the same component in order for customers to meet quantity requirements of high-volume parts. At the time of the IMM plant tour, the company was in the process of making eight washing machine tub molds for a major appliance manufacturer.

The company has a horizontal CNC machining center that is one of the largest this writer has ever seen. A machinist sits in a cab with the control panel, “driving” the spindle along the cutter paths. “We can rough faster at 90° than in a vertical machining center,” says Gougé. “We can’t get the chips out of the horizontal machine fast enough, so that’s why there’s a person sweeping the chips out of the way with a broom. When you’re removing that much stock in that machining center, the heat is contained in the chip, which is by design with the new carbide cutting tools.”

The cutters make metal chips as big as Fritos corn chips, and Triangle produces as much as 20,000 lb of chips every day. All the aluminum, steel, and copper chips are separated and recycled, as is the large amount of cooling fluid these huge machine tools use.

Big molds also present challenges for performing quality checks, which are performed in the quality department with a 10-by-10-by-7-ft coordinate measuring machine (CMM) as well as via on-machine inspection. “Most of our machine tools are equipped with on-board inspection software,” says Gougé. “That enables us to check certain points as it cuts via laser or probe inspection. We can also check wear on the cutter tools.” Triangle cuts all of its own custom cutting tools, and all of its carbide cutting tools are reground, which is also done in-house as a way to save money.

Baez adds that the industry has changed with respect to final fitting of large molds. Everything is machined to a “zero-cut” finish. “We expect no handwork when a tool gets to the final fit,” he says. “There’s no time for that in this industry for large molds. And today, we have full parting line contact, which makes the tools last longer—all due to the accuracy of the on-board inspections.”  

Vital Stats
Triangle Tool Corp., Milwaukee, WI
Facility size: 173,000 ft2
Markets served: Industrial and returnable material handling, large recycle carts, consumer storage products, and large appliance, heavy truck, and agricultural equipment components
No. of employees: 135
Work hours: Two shifts
Molding machines: Five, 500-3000 tons; Husky, Milacron
Moldbuilding equipment: 45 large CNC machining centers; 18 four- and five-axis high-speed machining centers; two gun drilling machines; two large fitting presses; two small fitting presses; gantry-style EDM with 10-by-10-ft working area; 18 cranes up to 100-ton capacity; two new OKK Shuttle machines; Unigraphics mold design CAD-CAM.
Mold technology: Extremely large injection and compression molds, standardized modular stack frames and stack molds; single-cavity molds to multicavity stack molds for large parts.
Other services: Molding tryouts, welding, special machining

Clare Goldsberry

About the Author(s)

Clare Goldsberry

Until she retired in September 2021, Clare Goldsberry reported on the plastics industry for more than 30 years. In addition to the 10,000+ articles she has written, by her own estimation, she is the author of several books, including The Business of Injection Molding: How to succeed as a custom molder and Purchasing Injection Molds: A buyers guide. Goldsberry is a member of the Plastics Pioneers Association. She reflected on her long career in "Time to Say Good-Bye."

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