Slinging MUDs

ASH Industries is taking advantage of recent advancements in CAM software to streamline dramatically its processes for making the tools used for molding medical parts. The first CNC programs for cutting mold plates, after the completion of the mold design, can be delivered to the shop floor in as little as 15 minutes. In some cases, the advanced cutting strategies incorporated in these programs make it possible to mill all of the mold plates within a single day.

These improved manufacturing efficiencies are the basis for the company’s SuperMold Program that offers a production quality mold and 1,000 molded parts for a set price. SuperMold parts are available within three different size envelopes and pricing varies accordingly. Small parts that fit within a 2" x 2" cylinder start out at $4,900. First articles for these are delivered in 3 weeks. Larger SuperMold parts take longer, up to 8 weeks. However, shorter lead times are negotiable under special circumstances.

According to ASH Industries’ president Hartie Spence, the ability to get molded parts so quickly and inexpensively is making medical device manufacturers think twice about using intermediary processes like stereo lithography and 3D printing for prototyping. The big advantage of this approach is that the medical device company can have a production mold ready to go as soon as necessary approvals have been obtained.

He said that improved manufacturing efficiencies, which allow his company to offer competitive pricing and fast turnarounds, is derived from a very skilled and focused manufacturing staff combined with advanced features that began to appear in its CAM software starting around 2009. The company uses Mastercam soffrom CNC Software, Tolland, Conn.

Figuring it out

In 1990, Hartie Spence was an electrical engineer working in the aerospace industry. His independent nature and lifelong passion for making things drove him to move back to his home in Louisiana and start a manufacturing business. He acquired the license to make a patented injection molded product that did not succeed commercially. After this failed initial venture, his primary remaining assets were some manufacturing space and an injection-molding press. He decided he would take a shot at becoming a custom molder.

By his own admission, Spence knew almost nothing about molding or moldmaking, but he did have a command of critical thinking and manufacturing processes. This allowed him to figure out how to meet the needs of a succession of customers. Spence estimates that his company is now working on the 20th generation of referrals from those first satisfied users. During the intervening years, the company has grown through good times and bad, to the point where 50 people are employed making and delivering parts from a variety of processes that include injection molding, silicone molding, roto-molding, and metal injection molding. Fourteen machines are used in these processes, and about 70% of this work is for medical device manufacturers.

Spence initially purchased molds from local tool & die shops, but he became frustrated because they could not consistently deliver what he envisioned. Subsequently, in 1996 he acquired a band saw, a surface grinder, and a 3-axis CNC mill with a rudimentary version of Mastercam for programming and began making his own molds.

“It’s a joke around here,” Spence says. “I made some really bad tools and there are people here who won’t let me forget it. Part of the problem was using a very basic level of software that required several hours of work to generate a simple program.”

He got past his initial struggles programming his CNC equipment by consulting with MLC CAD, his local Mastercam dealer. MLC CAD fortified him with versions of the software that were much more efficient for his needs, and its employees have served as manufacturing process consultants to the company through numerous software updates. Spence says his toolmaking operations really turned around when he turned over the programming to Eddie Higginbotham, a manufacturing engineer who programs all of the CNC mills and organizes workflow through the shop. Today the company has four 3-axis CNC machines, two plunger EDMs, and a 7-axis Swiss lathe.
 

Standardizing processes

Most of the SuperMold tools are MUD (master unit die) molds consisting of six or seven modular plates that slide easily into a standard frame. This approach both reduces the overall cost of tooling and allows for fast tool changes at the molding machine in keeping with just-in-time manufacturing. The MUD concept also makes it easy to modify individual plates rather than complete tools during the mold development process. During the past 8 years, Higginbotham has developed standardized processes for making MUD tooling that have dramatically improved his own programming productivity along with that of the company’s CNC equipment.

“The last 3 years have shown the most dramatic improvements based on the new toolpaths and the dynamic toolpath training I received from MLC CAD, our Mastercam reseller,” Higginbotham notes.
 

Templates for everything

When Higginbotham first started doing all of the CNC programming, he would start from scratch with each electrode or mold plate that came his way. He soon noticed that the many of parts that came in for CNC programming had common elements. Soon he was setting up programming templates within Mastercam so that whenever possible, repetitive tasks were done automatically, with feeds and speeds already established and optimized within the template.

He says, “With the advances Mastercam has made in the last three or four iterations, our productivity in the shop has skyrocketed. I am programming faster. I have templates set up for each of the mold plates and a template for the electrodes. I merge my geometry from SolidWorks into Mastercam. I’m picking lines, picking surfaces, right from my default file and programming faster than I ever thought possible. Electrodes that used to take me a half-an-hour or so, I am now programming in minutes.”
 

Fast, simplified toolpath selection

Higginbotham notes that programming toolpaths to cut the geometry indicated in the CNC program is almost instantaneous because he now relies on just a small number of material-aware toolpaths that will handle just about anything he needs. These include OptiRough, OptiCore, and Hybrid Finishing, a technique that switches cutting methods based on the shape of the part and automatically blends transitions between steep and shallow areas.

“I used to spend a lot of time figuring out what toolpath I was going to use to get at different areas of a cavity. Now Mastercam has these new dynamic toolpaths nailed down so well, I know the software will figure it out,” he explains. “I just pick the surfaces and set containment boundaries and let it go. It is actually fun.”
 

Much faster CNC machine cycles

Dynamic toolpaths do not cut blindly but are aware of the condition of the material during every stage of machining. They use this intelligence to adjust feeds and speeds, automatically, to avoid burying the tool. Cutting is done at high speeds at shallow radial cuts using as much of the tool’s flute length as possible. This approach minimizes tool wear and stresses on the part while, in many cases, significantly reducing cycle times.

“Cutting-wise, we have taken as much as 70% off some of our cycle times. For example, electrodes that used to take 5 minutes are coming off the machine in 30 seconds – so fast that it looks like an electrode forest over there. The guys in the shop are kind of spoiled because they don’t know how difficult graphite machining can be as far as chipping and breaking electrodes. With all my experience combined with these material-aware toolpaths, electrode scrap is practically nil,” Higginbotham explains.
 

‘That’s just what we do’

If CAM processes are highly standardized to optimize productivity, does this detract from the company’s ability to satisfy a medical devices customer’s special requirements for fast and flexible responses to product development emergencies?

This question was answered recently when ASH Industries was asked to develop tooling and mold three close-tolerance parts – and everything had to be done within a week.

Higginbotham says it was actually easy to fit the programming, CNC machining, and mold assembly into the company’s workflow: “I got with the guys on the floor and told them that we are not going to change a thing about our established workflow, just the order of what we do to keep this work moving forward. Between my programming and the guys on the floor, nailing everything running on their machines, the job was done, sampled, and shipped Friday afternoon.

“This would normally be a 3- or 4-week part,” he continues. “We cranked out the programming and machined components in 3 days so Thursday and Friday could be devoted to molding and final assembly. Management was really impressed; they thought we really busted ourselves on that one, when actually, that’s just what we do.”

The SuperMold Program has been a very popular ASH Industries’ program. It has been an instrumental contributor to the company’s 30% growth in sales with only a 10% to 15% growth in manpower during the past 3 years. Spence explains that most of the productivity increases have been used to benefit the customer in the form of faster turnarounds and competitive pricing.

ASH Industries
www.ashindustries.com

CNC Software Inc. / Mastercam
www.mastercam.com

Elizabeth Engler Modic is editor of TMD and can be reached at emodic@gie.net or 330.523.5344.