Mold manufacturing technology has reached new heights via faster machining; more flexibility in creating cores and cavities with increasingly complex geometries; and automation that improves productivity and efficiency. All of this provides moldmakers with a greater competitive advantage in terms of both time and cost. But that advantage doesn’t come easy—or cheap.
Advancements with the greatest impact on productivity appear to be in the areas of machine software and controls, according to moldmakers and machinery suppliers. Technology such as material flow simulation is being adopted by moldmakers at a much faster rate than a few years ago, while 3D printing/additive manufacturing (AM) has been slow to find a niche among moldmakers.
The use of high-speed machines (HSMs) is now fairly common among mold shops, even though it took a while for many companies to optimize the high feed and speed rates it offers. That was primarily due to cultural mindsets among experienced moldmakers: they were used to familiar processes and reluctant to push the envelope with HSMs.
However, most of the mold shops that have embraced and mastered HSM now realize that they have a stable process—one that is predictable and repeatable—and are looking at additional ways to enhance productivity and throughput via automation, explained John Bradford, manager of turnkey and automation proposals VCM/EDM for Makino Inc. (Auburn Hills, MI).
The primary advantage of automation in mold shops is that—if correctly applied—it can dramatically increase machine uptime and machine utilization rates. Bradford noted that most moldmakers cannot be profitable with machine utilization rates of 30–40%; machines need to be utilized at a rate of at least 70–75%.
“The most effective way to control costs is to have an automation system for functions such as loading and unloading materials, and a controller for scheduling and managing the workflow,” Bradford said. “With automation, we’re targeting machine uptime, manual labor and more efficient workflow through the machine by using more cell-control software.”
Bradford said that the critical factor for mold shops looking to automate is process stability: “There are newcomers out there and they’ve not yet achieved process stability. They’re still trying to embrace these new HSM centers, and we’re trying to coach them to have things in place that allow them to achieve untended operation, obtain predictable results and have full control of their processes before they go into automation.
“Many of the customers that jumped into HSM 10–15 years ago have the kinks worked out and have achieved the consistency that allows them to invest successfully in automation,” Bradford continued. “We’ve definitely seen a spike in machines purchased with automation—about four-fold over the past three years. That said, it still goes back to the basic point that you first need a predictable and repeatable process. If you do not, automation can magnify problems in the shop.”
With control being critical to the successful and efficient operation of machine tools in mold shops, many machine manufacturers are emphasizing advances in their control systems. For example, UltiMotion from Hurco Companies Inc. (Indianapolis) is “the biggest advancement in control technology” since the company launched its WinMax product, according to the company.
UltiMotion, introduced five years ago, represented a huge leap for Hurco in that it is a combination of the company’s proprietary control technologies and advanced control theories. This combination gives customers the ability to cut higher quality parts in a shorter period of time, especially when high-speed machining. “Those parts typically have complex geometries and involve repetitive tasks, such as drilling and tapping,” said Greg Volovic, president of Hurco.
Mike Cope, product technical specialist for Hurco, elaborated. “UltiMotion is a multicontrol system that is good for moldmaking as it provides more control over tolerances and the way things are processed. It delivers smoother machine motion, better surface finish and shorter cycle times,” Cope said.
On the heels of UltiMotion, Hurco began releasing high-speed machines used in moldmaking that offer faster spindle speeds as well as direct-drive linear axis motors for smoother motion. “The BX40i is a bridge-style machine targeted to the mold industry and offers a thermally stable platform,” Cope said. “It has rails on both sides of the table that allow the entire head to travel back and forth. This helps eliminate some of the thermal problems that C-frame machines encounter.”
Precise Machines and Automated Inspection
Scott Blankenship, director of tool manufacturing at Canon Virginia Inc. (Newport News, VA), said that CVI has recently invested in two major technologies to improve productivity and accuracy: three new five-axis precision machines from Kern Microtechnik GmbH, and a Capture 3D automated, noncontact 3D inspection system capable of taking an image of eight million points to capture the entire shape on the surface, which helps ensure quality in cores and cavities with very complex geometries. “The Capture 3D system performs in-process checks to measure electrodes and finished parts, allowing us to see the true stack-up of the tool,” he said.
Blankenship added that for CVI, accuracy and workholding were key factors in choosing the Kern machines. “They have a high-end controller and offer functionality that allows us to cut our manufacturing time,” he said. “The big opportunity is setup reduction and the ability to make complex parts for our customers in aerospace and automotive. On one of the Kern machines we have a System 3R WorkPartner 1+ compact loading system from GF Machining Solutions and are in the process of implementing the Renishaw Productivity + software to be able to run lights out. This allows us to pick up parts and make compensations on the fly.”
Will Moldmakers Adopt Hybrid?
Machine tool technology advancements include adding AM capability via “hybrid” machines that offer both traditional subtractive and new additive capabilities. Over the past few years there’s been buzz around hybrid machine tools, but moldmakers don’t appear to be embracing the technology in a big way yet.
Some machine tool builders believe these hybrid machines will have an impact in a number of moldmaking areas, particularly with extremely complex interior features in core/cavity production that can’t be done subtractively because of where features are located. While some machine tool builders believe the market will eventually accept hybrid technology, others say that, because moldmakers tend to be slow adopters, it could take up to 20 years for hybrid machines to catch on.
Still, that hasn’t stopped builders from introducing innovative AM technologies to the market. Mazak Corp. (Florence, KY), for example, introduced its first hybrid machine, the Integrex i-400AM Hybrid Multi-Tasking machine nearly 18 months ago. The company said it offers a “new, innovative alternative to conventional processing in terms of part design and machining.” This past December, Mazak introduced the Integrex i200S AM, with a multilaser deposition system that provides both additive and subtractive capabilities. “Shops can not only turn, mill and drill, but also build part features and perform laser marking all on the same machine and in single setups,” said the company.
Also in December, Mazak announced the Variaxis j-600AM Vertical Machining Center featuring a Wire Arc-type metal deposition system. “The system incorporated a standard wire arc-welding head mounted on the machine’s headstock to deposit material layer by layer and grow near-net-shape 3D forms,” said Mazak. “The system deposits material faster because it uses wire instead of powder.”
Last summer, Hurco announced it would debut VMCs with the ability to transform their WinMax part programs to a 3D printed rapid prototype directly on the CNC machine using an optional spindle-powered wireless accessory. “The new Hurco 3D Print Head allows users to take full advantage of the size of the machining center,” said Volovic. “The portable accessory is powered and controlled by spindle rotation so there are no wires to install, and it can be easily moved.”
Hurco’s Cope further noted that the printing head is removable from the spindle so that any type of machine can become a 3D printer. “This is pretty new technology and we just started selling it at IMTS in September,” he said. “As for whether or not moldmakers will adopt this technology, that industry hasn’t found its niche [for 3D printing applications] like everyone thought it would.”
However, Volovic believes that many of Hurco’s customers “are true innovators” and that the 3D Print Head Adapter for CNC machines will find a place with those who are open to the advantages of additive.
New mold heating and cooling technologies can help molders reduce cycle times and improve part quality. One technology that seems to be catching on—albeit more slowly than many expected—is 3D-printed metal conformal cooling channels. Interest in this technology has increased considerably over the past decade, especially among OEMs in industries such as aerospace and automotive.
Two primary technologies, Direct Metal Laser Sintering (DMLS) and Selective Laser Melting (SLM), have been adopted rather quickly by OEMs for the purpose of creating conformal cooling channels in molds. Using DMLS or SLM provides the ability to hold molding pressures without the potential for leakage.
RocTool Inc. (Charlotte, NC), a developer of mold heating and cooling technologies, recently conducted a study to identify a range of resin materials that can be successfully used with RocTool’s molding technologies to produce high-quality parts with high flow and reduced cavity pressure. RocTool worked in conjunction with RJG Inc. (Traverse City, MI), which specializes in injection molding training, technology and resources, to demonstrate the advantages of RocTool’s technologies. Those advantages include improved flow, reduced cavity pressure, high surface replication of the mold and significant gloss improvement in molded parts.
One of the main challenges in the plastics industry is reducing overall part thickness. The flow increase produced by RocTool induction heating technology delivers new design opportunities by pushing the limits in creating thin-wall applications, according to the company. To enable these opportunities, RocTool developed a specific spiral mold to calculate the flow length while pressure sensors were implemented by RJG to assess the capability of RocTool technology to improve mold filling and reduce cavity pressure.
“We do all of the engineering work using thermal simulations with induction heating,” said Steve Verschaeve, vice president of North American business development for RocTool. “We then provide a 3D model of the heating and cooling module to tell the moldmaker what to cut into the mold in order to achieve needed cooling requirements.” Verschaeve noted there are other ways for this technology to be adopted in molding processes—particularly in applications such as packaging and medical.
Changing a ‘One-Off’ Process
Darcy King, owner of Unique Tool & Gauge (Windsor, ON), a mold and gage manufacturer specializing in molds for the automotive industry, continues to find ways to innovate what is typically a “one-off” process. Recently, King bought CAD/CAM software from Cimatron Technologies Inc. (Novi, MI) that offers “raw computing power” that allows Unique Tool to automate its mold design.
King explained that a program is written for each customer and each molding press into which the mold fits. “Every time I design a particular mold, all the details—the mold parameters the customer wants— are already in that program, which eliminates the potential for human error,” said King.
Every customer has its own mold building parameters. The net effect of automating the design process is “tremendous savings” because the mold design parameters are already there. “We’ve developed a standard and each parameter matches that standard, meaning the mold is right the first time,” said King.
The company uses software tools to automate much of the mold design process, saving time and money while creating the opportunity to simulate the mold function and operation. “We can make sure that the mold has no restrictions and that all the angles and features we designed into the mold work concurrently together,” said King. “When you are creating complex action and mechanisms, simulation saves time and money, improves quality and eliminates the need for lots of last minute changes.”
Unique uses Moldex 3D mold fill simulation via Cimatron, which provides the computing power that allows the mold maker to perform two or three mold fill simulations in the time it used to take to do one. “We invested in building a really complex hardware system to run the software, which is why we can be more efficient in mold design,” King commented.
“We’re finding that the more technology we incorporate, the more moldmaking is actually process driven,” he added. “It’s still a customized manufacturing process, but we’re trying to ‘productionize’ what is typically a one-off environment in order to make it more process-oriented. Over the last 10 years, moldmakers have done a really good job of going in that direction.”
Ready for New Technology?
Makino’s Bradford noted that technical readiness and cultural readiness are both key when it comes to adopting new technology such as automation. “You must have the ability to embrace automation on a technical level,” he said. “The skill level requires multiple new cultural habits within a shop—how parts are set up on the machine challenges how programs are created and how work is passed from one station to another. How we schedule work and manage the schedules all go hand in hand. You’ll run into the cultural obstacles in shops where people are not ready. They’re used to doing something a certain way; you have to tackle the cultural aspects first.”
Cope of Hurco concurred, adding that he believes moldmakers are becoming more open to automation and other advanced technologies, such as high-speed machining with lighter cuts and the capability of new machine tools to use advanced cutting tools, which results in faster machining. “Controls have more memory and look-ahead. Spindles are getting larger and faster,” said Cope. “They’re always pushing the envelope—‘if we can do this, now we can do that.’ We’ve come so far with the spindle that we’re working on the controls now. Someday, someone will come out with something really revolutionary, but for now we’re trying to squeeze the most out of the technology we currently have. Now is a good time to be a moldmaker.”