Stama MT 733 series vertical spindle mill-turn centers handle 6-sided/ simultaneous 5-axis machining, including milling and turning from bar or chucked parts in lot sizes as small as one. One- and two-spindle machine configurations machine aluminum to high-alloy steel bar from 15mm to 102mm diameter and lengths of 1,020mm. It can produce workpiece lengths up to 250mm, and chuck parts up to 250mm in diameter. Milling spindles offer speeds to 20,000rpm, turning spindles to 4,200rpm, and traverse speeds to 56m/min. Spindle acceleration to 1.3g minimizes cycle time while completely processing parts.

MT 733 series models are compatible with bar or chuck component machining for complex parts from bar, bar segment, semi-finished component, or casting. The MT 733 one, MT 733 one plus, and MT 733 two plus versions are also capable of either/and simultaneous – bar and chuck work.

A polymer concrete base frame in a thermo-symmetric structure offers high heat capacity and low heat conductivity. Adaptive software for active milling spindle compensation reduces temperature-related variations in the Z-direction.

Chiron Group
http://www.chironamerica.com

Modern technical ceramics offer unique material properties and features, compared to metals and plastics – typically high hardness, good wear resistance, high compressive strength, and minimal susceptibility to extreme chemistry.

Some ceramics, such as a chemical vapor deposition (CVD)-produced silicon carbide, exhibit high thermal conductivity, along with electrical conductivity, which allows EDM machining. Aluminum nitride also has high thermal conductivity but acts as an electrical insulator.

When developing an application for ceramics, working with material experts early in the design process is critical to understanding these properties.

Technical ceramic challenges

Technical ceramics, such as alumina or zirconia, can be produced by pressing powders and firing to create a green fired ceramic. This material is soft, so adding holes, flats, or other features is simple and cost-effective using single-point turning operations.

The next step is sintering. This process causes the part to shrink, making it difficult to hold high-accuracy tolerances or sizes. If high precision is required, machining must be done after the material has been fully fired. This is typically tolerance- and feature-driven and can add considerably to the cost.

Fully-fired technical ceramics are machined by time-consuming grinding processes, using tools or wheels that have diamonds embedded into a matrix of metal or glass. Tight tolerances, surface finish improvements, and polished surfaces can be achieved by using diamond suspended in a liquid (slurry).

Medical applications

Many high-end medical applications, such as heart pumps (LVADs), benefit from the durability of precision, biocompatible mating parts. Known for their long service life, without the concern of contamination or wear, ceramics offer a solution. For example, sapphire, the single crystal version of aluminum oxide, is transparent and can be fabricated into completely inert, wear-resistant precision windows and lenses for endoscopes.

An added benefit is that medical ceramics can withstand the rigors of sterilization.

Insaco has been working with these materials for more than 70 years. Our experience suggests that these materials are selected because of need, given the design considerations. While we recommend alternative materials be considered, a design engineer should always keep technical ceramics in mind. The material properties of ceramics often make them the only possible choice.

Insaco Inc.
http://www.insaco.com

Tooling choices determine the cost of producing stamped metal parts for medical equipment, such as carts, cabinets, enclosures, and user workstations that safeguard sensitive controls, electronics, or hardware. Expensive hard tooling offers the lowest cost-per-part by ensuring high productivity, while more-affordable soft tooling is slower.

Unfortunately, estimating initial production requirements for new products is challenging; forecasts are often conservative or unrealistically high. With this inevitable uncertainty, original equipment manufacturers (OEMs) are hesitant to invest significant dollars in hard tooling, which can cost tens of thousands of dollars upfront. Instead, less expensive soft tooling options may be selected initially, even if they increase the price-per-part.

At the appropriate demand tipping point, medical equipment and instrument manufacturers should transition to hybrid tooling, staged tooling, or progressive dies that speed turnaround time and drive down the price.

This laddering-up of tooling options requires assessing at each plateau whether greater upfront investment in tooling will pay off with a relatively quick return on investment (ROI). Since tooling plays such a key role in this equation, it also means working closely with OEMs to evaluate the best available tooling options at any time.

“As production requirements increase, transitioning to a more efficient type of tooling can save some medical equipment manufacturers tens of thousands of dollars a year with a ROI measured in weeks or a few months,” says Bob Denholtz, president of DureX Inc., an ISO 9001 registered contract metal manufacturing company with a 120,000ft² facility in New Jersey. “Any good metal parts supplier should be able to help the OEM determine the most cost-effective tooling for their situation.”

Although tool selection for the medical industry involves variables such as part size, metal thickness, complexity, and finish, the cost-per-part often depends on the type of tooling used. This progression generally ranges from soft to hard tooling, hybrid approaches, staged tooling, and fully progressive dies.

Soft tooling

Low-volume part manufacturing for the medical industry often involves soft tooling – tools made from pre-hardened steel or other materials – for sheet metal fabrication. Usually this entails having a flat or slightly formed part that has holes, slots, or tabs punched in it by a CNC laser or turret punch press, followed by bending using a press brake.

“Soft tooling typically costs $75 to $500 but can cost up to $2,000 to $3,000 for more complex parts,” Denholtz says. “This can work for medical part prototyping and low-volume production orders. However, it can take several minutes of machine time to make each part, depending on its complexity, so the cost per part is higher.”

One strategy for medical equipment manufacturers to lower or eliminate soft tooling cost is to borrow the tooling from a supplier. Because DureX has been serving a variety of markets for more than 30 years, they have built up an inventory of soft tools in many sizes and shapes. When appropriate, these tools can be put back in service, eliminating tool costs.

Hard tooling

When critical tolerances are required and/or volumes increase to 15,000 units or more annually, OEMs often benefit from moving from soft tooling to hard tooling – tools precision-machined from hardened steel – to reduce costs. According to Denholtz, hard tooling can cost $5,000 to $300,000 depending on size, complexity, and whether it is designed to produce a finished part.

“One OEM started at 500 parts per month with soft tooling,” Denholtz says. “However, when production requirements increased to 4,000 parts a month, we suggested they move to hard tooling to reduce the price from $22 to $15 a part. With a hard tooling cost of about $85,000, they achieved ROI in about four months.”

Hybrid tooling

As the name implies, hybrid tooling is a combination of soft and hard tooling. Depending on the part, it might begin as a flat piece of metal that is punched or formed with a soft tool, then further formed by a hard tool.

For example, an enclosure could be started in a turret that punches all the holes and slots before it is moved to a hard die that forms up the sides into a box in one operation.

“Instead of putting a flat piece of metal in a brake and hitting it four times to bend the two sides and two ends, we could use a die and hit it once. So, it only takes 30 seconds or less to make the entire part instead of 2 minutes,” Denholtz explains.

Staged tooling

To create metal parts for medical equipment manufacturers at even greater speed and volume as well as lower price per part, staged tooling can be used. Metal parts move between multiple stage tools, so the work is performed in unlimited processes that use hard tooling.

“For example, instead of taking 5 minutes in a machine to punch all the features individually using a soft tool, we could make a blanking die and punch everything in one hit in seconds,” Denholtz says. “Then we could put it into a forming die and form it into shape.”

Progressive dies

The fastest, highest-volume part production can be achieved by a progressive die. This accomplishes multiple operations in a single process using hard tooling. Typically, a metal coil feeds material into the press, and it stamps material into shape as it progresses through the machine – adding a new feature with each stamping until a finished part exits the machine.

Denholtz gives an example of a customer that was spending about $125 for a metal card cage that held circuit boards.

“When volume rose to 1,000 parts a week, we reduced the cost to $55 per cage by switching to multiple staged tools,” Denholtz explains. “Although the hard tooling cost was substantial – about $350,000 – the OEM achieved ROI in only 5 to 6 weeks.”

Value added

Medical equipment manufacturers may benefit from working with a contract manufacturer with added-valued services such as finishing and assembly to further streamline the process.

“The ability for a contract manufacturer to take a medical part from cradle-to-grave from design through prototype, into full production of a fully assembled, finished product – even including fulfillment – can further reduce costs and allow the OEM to focus more on core competencies,” Denholtz says.

Whatever the scope of manufacturing, medical equipment manufacturers can benefit by working closely with metal part suppliers to optimize the tooling for the job. In doing so, they can significantly reduce per-part costs with a surprisingly fast ROI.

DureX Inc.
https://www.durexinc.com

Using specific volumes of material to sculpt a part, layer-by-layer, offers advantages that expand the boundaries of feasibility in manufacturing.

While the technology can create plastic or ceramic parts, metal AM is growing and developing quickest.

While it’s not a cure-all or miracle solution – a number of key applications can be most efficiently handled with metal 3D printing – the list is growing by the month. The detailed analysis that should accompany any decision to integrate AM into a process is too vast in scope to cover here but following are a few introductory points to help.

PHOTO: 3D Hubs

Medical advantages from metal AM

In general, metal AM is the right solution for production of components that are highly intricate, specific, or both. Advantages of metal AM are:

• Mass customization
• Lower cost in low volumes
• Design freedom with high complexity

The additive process allows the formation of complex internal geometries impossible to achieve with traditional manufacturing. AM allows for custom parts to be made at high volumes because it doesn’t require molds. It’s easier and less expensive to produce a high-quality, unique part by importing a digital drawing than it is to tool and set-up traditional manufacturing. Injection molding and other methods are more efficient at higher volumes, but it’s a clear winner for highly detailed, low-run applications.

Medtech, more than most industries, is characterized by dependence on custom equipment. Metal 3D printing applications include joint replacements, stents, dental inserts, and prosthetics – parts singular in their size and shape.

Joint replacements, surgical instrumentation

Consider a hip replacement. A hip has a demanding list of traits to perform its function:

• It must fit the patient’s unique socket shape
• It must flex, turn, and rotate in at least a reasonable imitation of the original
• It must be safe to implant into a patient’s body

Ten years ago, an Italian surgeon inserted the world’s first titanium 3D printed hip into a patient. Despite early questions about how the joint would hold up, today, the pilot patient is doing “extremely well,” and some experts think it may be reasonable to expect these joints to last 20 years or more. More than 100,000 3D-printed metal hip joints have since been used as replacements.

Another prominent example is in surgical instrumentation, which have only recently begun to be 3D-printed in volume. A very delicate open-heart surgical procedure called keyhole heart surgery was an excellent candidate for innovation. Surgeons wanted a tool that they could dismantle and pass through a tiny incision in the heart. A 3D-printed stainless-steel tool emerged as the solution.

In just three months, the entire suturing procedure was revolutionized and product development cost less than $20,000. Examples like these are becoming increasingly commonplace across all branches of medtech. While metal 3D printing isn’t the perfect manufacturing solution for every industry, it has already changed how we think about what’s possible in medical devices. There is promise for continuous leaps forward.

3DEO
https://www.3deo.co
MD&M West 2019 Booth #447

About the author: Matt Sand is president of 3DEO and can be reached at msand@3deo.com or 310.694.6847.