Digital twin helps an engineer succeed with CNC
A medical manufacturer diversifies its business and produces plastic-injection tooling with minimal CNC experience
I thought that the digital twin was just marketing hype, but it truly depicts what will happen. I can program any part with ESPRIT without a doubt in my mind that I will achieve the results that I want.Harit Patel, Production Engineer, National Medical Products
National Medical Products uses ESPRIT CAM software to power advanced machine tools, diversify production capabilities, and eliminate the need for outsourcing.
Harit Patel was a CNC programming novice when his employer, National Medical Products, acquired a pair of advanced CNC machine tools and the computer-aided manufacturing (CAM) software needed to drive them. As one of the company’s production engineers, it was up to Patel — who graduated in 2020 with a degree in mechanical engineering — to produce and manufacture the tooling needed to both keep pace with demand for its popular medical product and diversify business.
For more than two decades the company has met with continued success due to the popularity of its J-Tip™ needle-free injection system. Developed, manufactured, and sold by National Medical Products, the J-Tip is a single-use, subcutaneous injection device that uses a high-pressure chamber to administer local anaesthesia in preparation for traditionally painful needle-based procedures. The company now sought to break into new markets while continuing to develop proprietary products.
“We want to continue to diversify our portfolio in healthcare,” Patel said. “We’re seeing a lot of innovation in the healthcare industry, which gives us the opportunity to innovate existing products and develop new ones for patients, all around the world, to attain effective healthcare.”
The tooling that the company has used for years to produce the J-Tip was manufactured manually on site by a long-time employee who has since retired. Instead of outsourcing tooling development and production offshore, Patel works closely with an outside engineer to develop tooling that he can produce and tune in house.
“A lot of companies that used to outsource tooling production overseas are now onshoring because it’s either around the same price or less expensive, and the lead times are better with current market demands,” Patel said. “Higher logistical costs caused by tariffs, materials, and transportation fees are also an incentive for doing as much as possible domestically.”
More than a well-oiled machine
National Medical Products opted to fully embrace the modern tools of the trade to make its new tooling and, in 2021, acquired two Okuma CNC machine tools equipped with Okuma OSP controllers. The new line-up is comprised of a 3-axis mill with a +2 positional turntable and a 4-axis lathe with an interpolated Y axis, both of which provide flexible machining capabilities that ensure the company can efficiently produce just about anything.
The mill’s positional turntable enables the company to perform 3+2 or positional 5-axis machining, which entails locking cutting tools into place to machine in two additional axes so that workpieces can be machined from all sides — albeit not simultaneously. Like simultaneous 5-axis machining, however, 3+2 machining supports the use of shorter tools for better cutting stability and surface quality, among other benefits.
In that same vein, the interpolated Y axis on the company’s lathe makes it possible for Patel and his team to accomplish more in a single operation, and with a single machine tool. The ability to perform off-centre milling operations — such as drilling — on turned parts eliminates the need to transfer workpieces to a mill for additional operations. Use of both the turntable and interpolated Y axis increases the team’s ability to perform more operations in one go while reducing laborious machine setups that increase opportunity for error.
Right CAM for the right machine
Because the company had never used state of the art CNC machinery, it was completely unfamiliar with the CAM software needed to drive it. After investigating their options, Patel and his team chose Hexagon’s ESPRIT software because the solution is developed specifically to drive advanced machinery using edit-free NC (numerical control) code.
Operations performed on multi-axis and multi-channel machinery can be difficult to program and accurately simulate. This is especially true in cases where the CAM system isn’t working with machine-specific post processors, or software that translates the NC code — or G-code — generated by the system into commands that machine tools understand.
Since CNC machinery gained significant traction in the 1990s, experienced machinists have edited G-code at the control to make changes to the toolpath generated by CAM software as needed — often to make the toolpath more efficient, but also to make it safer for machining.
The ongoing expansion of machine-tool capabilities has made it possible to machine highly complex parts that simply couldn’t be made with CNC machinery 30 years ago; the trade-off is that those advanced machines are much more difficult to program.
Machinists who could manually program the parts of yesteryear would have to comb through thousands of lines of code over several days to produce today’s complex parts, such as those with freeform surfaces. Today, less experienced machinists often don’t have the knowledge required to edit code at the control, and the increasing complexity of parts means the need for robust and reliable CAM software is greater than ever regardless of a machinist’s level of experience.
“There are a lot of complicated elements, especially in the lathe, that any ordinary CAM software wouldn’t be able to replicate for safety and to prevent crashes or other types of damage,” Patel said. “We weren’t sure what software to go with, but we chose ESPRIT because they work closely with Okuma, and we assumed that they would really have the support dialled in. Little did we expect, they really meant they work closely with Okuma.”
Through the ESPRIT product line, Hexagon is a member of Okuma’s Partners in THINC network, a collection of partners that work closely with Okuma to overcome challenges shouldered by mutual customers. Stationed inside the Okuma America Corporation headquarters in Charlotte, North Carolina, ESPRIT personnel work with Okuma staff to fine-tune ESPRIT’s machine-specific post processors and develop solutions that solve customer problems.
The ESPRIT digital twin is comprehensive, giving confidence that programs will deliver the intended result from first cut.
Seeing is believing
Developing and producing plastic injection tooling is inherently complex due to, among other things, unpredictable material behaviour and an abundance of components that include moving parts. As such, mould production is difficult for any manufacturer without a tooling background and especially challenging for someone entirely new to CAM software.
“I learned as I went, so making the tooling wasn’t too difficult,” Patel said. “It took a little bit of patience, but we were able to replicate tooling with the software.” Patel found that the digital twin generated by ESPRIT, which graphically represents his machining environment, was especially helpful in ensuring that he could use his complex machinery with confidence.
“If you overlook something or are one decimal place off, your workpiece and/or machine could become nothing more than a paperweight,” he said. “The software allowed me to see everything before I started machining, and it told me if something was about to crash and when I needed to check my clearances. I thought that the digital twin was just marketing hype, but it truly depicts what will happen. I can program any part with ESPRIT without a doubt in my mind that I will achieve the results that I want safely.”
The ESPRIT digital twin represents stock, the machine tool, and vendor-specific data for cutting tools, tool holders, and workholding. The software’s simulation capabilities are based upon the accuracy of this digital twin and are enhanced by machine-aware artificial intelligence (AI). The software’s patent-pending AI engine represents a change in the way that CNC machines are driven, as it uses AI to simplify programming, optimise toolpath, increase tool life, and improve machine performance.
Links between machine movements are powered by the AI engine to automatically generate collision-free rapid positioning between cutting cycles. These links are optimised for the machine, tooling, and setup for automatic and safe positioning between cutting and non-cutting operations, such as tool changes and part handling. This results in reduced cycle time, simpler post processing, and link solutions tailored to machine requirements. This built-in intelligence helps Patel navigate the process of programming the sophisticated machinery while achieving machining efficiency and meeting quality requirements.
On top of restarting the in-house production of plastic injection moulds and continuing to develop and manufacture proprietary products, National Medical Products also seeks to diversify its capabilities by producing one-off parts and small lots to achieve higher utilisation of the new machinery.
“ESPRIT has really elevated the game,” Patel said. “After using the software for a few months, we can produce one-off aluminium and steel parts and, most importantly, we can produce tooling internally at a faster rate and within internal control. There was a bit of a learning curve because I had very minimal CAM background, but after the second training session it really clicked and my ability to start using it alone became dramatically better.”
Patel notes that the support provided by the ESPRIT team helped him to quickly learn how to utilise the company’s investment in machinery and software.
“When I have a question or am not getting the results I want, I’m just seven digits away from getting the answer I need,” he said. “I didn’t know CAM was even a thing until a year ago, so if I can learn how to create tooling and one-off parts in a couple of days, it shows that the software is powerful enough to help those without a CAM background quickly elevate their skills and produce precision work.”