HSM Technology Enables Mold Maker To Boost Productivity

Founded in 1959, Advance Mold and Manufacturing, Inc. (AM&M) is located in a temperature-controlled production facility in Manchester, Connecticut. The 30,000-square-foot building also houses Vision Technical Molding (VTM), a custom molding operation specializing in complex, tight-tolerance medical products. VTM also QC-samples AM&M’s molds. Although the two sides are separate businesses, they are also partners, connected within the same building. AM&M occupies 18,000 square feet of the building and employs 65 people working two shifts, 6 days per week.

AM&M builds approximately 200 molds per year, machining as much as 300 tons of material—ranging from stainless steel to graphite electrodes—for small, accurate mold components. About 20 percent of the company’s work travels next door to partner VTM. AM&M handles an array of work, with an emphasis on complex precision components for markets with counter-cyclic demand patterns such as automotive, medical and consumer/electronics.

At $11 million in annual sales and with an annual growth rate of more than 10 percent, the company says it is always on the move to sustain its challenging growth curve. AM&M also perceives competition from China as a significant motivator in its desire to stay abreast of new technologies.

“The cost difference between a Chinese-made mold and our product can diminish quickly when time, quality and service are factored in,” observes Steven Arnold, president of AM&M. “We can excel at providing services for customers who can’t tolerate delays because of quality glitches, distance and debugging, or who have urgent design-change needs.”

Mr. Arnold also believes that the company can differentiate itself from others by qualifying even complicated molds in-house and by performing complete first-article inspections.

Pressure on throughput and more stringent demands for precision convinced the company to add a high speed machining (HSM) cell to its equipment list. In February 2005, AM&M installed two HSM 400s from Mikron (Lincolnshire, Illinois), mated to an automated, ten-position pallet system with the capacity to accommodate 90 electrode holders with robotic support. The three-axis, 42,000-rpm vertical machining mills each feature automated toolchangers capable of holding as many as 68 tools. Both units have probing capabilities with laser tool measuring and compensation. In addition, a robot from Erowa Technology, Inc. (Arlington Heights, Illinois) changes pallets when workpieces or setups change. It also automatically changes grippers when changing out graphite electrodes.

The Mikron mills are designed for precision and high throughput. Precision begins with rigidity, which is achieved with a monoblock machine base set in polymer concrete, says the manufacturer. It is the basis for solid damping in an accessible mill. The HSM 400 machines are equipped with high-performance motor spindles that provide varying speeds and torque.

The level of automation is conducive to high throughput. Served by a robotic pallet system, the cell enables staging and setup during operation, extending the system’s production hours with much of the process conducted unattended. To maximize flexibility, the Mikron 400s each use automated toolholders capable of 3-second tool changes. According to the manufacturer, this makes it practical to economically use tools with short operating times—drilling, countersinking, threading and so on.

AM&M reports that the installation and setup of the new cell went smoothly. The company attributes the ease with which the cell was implemented to the system being specifically designed to work in tandem with the Erowa tooling robot. With the integration in place, the company was able to progress to startup 4 days after the installation.

The new mold cell replaces two bed-type mills that were struggling to keep up with production demands and quality standards. The equipment required hand-loading and additional operators. Another concern was the moving weight and mass of the machine components, which compromised accuracy. Thermal creep, as the production room and equipment gained heat, required constant checking and compensation to adhere to specifications.

“It was clear that the move to HSM would enable us to stay ahead of the technology curve,” says Mr. Arnold. “Today, we are focused on dramatically reducing leadtimes and increasing throughput while maintaining accuracy.”

According to Vincent Brown, CNC electrode/high speed mill department manager, the new cell has done just that. “With the HSM cell, we’ve seen our capacity grow by nearly 300 percent,” he notes. “We are also pleased with the new programming software. The ability to change priorities, enter new jobs into the system and remotely monitor operations has yielded various improvements.”

Setup time has been minimized because of a high degree of integration between the Mikron 400s and the robot. Mold parts are being produced in roughly half of the previous manufacturing time. The two mills are averaging a combined 240 production hours per week, with the brunt of this estimate characterized as “lights out.” Accuracy and repeatability have been improved as well.

“We can place as many as 100 electrodes of different shapes and sizes in the system,” explains Mr. Brown. “The laser probe offsets the Z position, and the machine does the rest automatically—unattended.

“Given the speed, accuracy and repeatability achieved by the new HSM cell, our staff can now concentrate on keeping the cell running as opposed to calibrating, checking and making the frequent adjustments that were previously required,” he continues. “Throughput is so much improved that, ironically, the increased number of finished workpieces sometimes causes bottlenecks in inspection.”

In addition to the productivity gains, AM&M has noticed that the system software allows mid-production changes that might be difficult or nearly impossible to handle with conventional mold milling systems.

“Recently, a customer called with an engineering change on a consumer electronics job 2 weeks into production,” explains Mr. Arnold. “We were able to quickly re-prioritize our work already in process in the machining cell and meet the customer’s needs with little or no impact on the final delivery.”

Mr. Arnold says that mid-production engineering changes occur more frequently because of the competitive marketplace and the shortened product life cycles that manufacturers face. Using the HSM system software, the company is able to initiate “on-the-fly” changes to compensate. The software also provides remote monitoring and alerts.

“I regularly check our job status from home,” Mr. Brown points out. “However, the system is also capable of alerting me of a change or decision point. I can halt production of one phase because of a pending change and then move on to the next job in line.”

In the near future, AM&M plans to automate production flow by linking the HSM cell to its Charmilles CNC sinkers. Like the HSM cell, the Charmilles equipment is currently running unattended during second-shift operations with remote monitoring. Once the new software has linked the two operations, the company projects a resultant boost in productivity.

“Combining our HSM cell with our EDM department is the next logical step in our automation strategy,” states Mr. Arnold. “It brings together the right combination of processes for meeting customer requirements and maintaining a competitive position.”

“Our capabilities enable us to provide a 4-week leadtime to build new molds, even with complex, multi-action molds,” he continues.