A machining shop in Somerville, South Carolina invested in HORN USA, WTO and Doosan to significantly increase tool life.
Facing a large order of 400,000 pieces per year, a machining shop in Somerville, South Carolina needed to develop a process to provide the required cycle time and tool life to maintain the required profitability. The task was to machine a large-volume part made of 8620 steel, which was designed with complex internal splines.
The shop owner originally purchased two Doosan lathes from Machinery Solutions Inc., a machine tool dealer in Lexington, South Carolina (no longer representing the Doosan series), and a standard SBU105 broaching system from HORN USA Inc. Early in the project, it observed that the broaching unit originally installed with the machine was not strong enough, so other options were discussed.
“We started with standard broaching inserts, and due to a lot of chatter, we started to experience tool life issues,” explains Michael Morgan, application/sales engineer at HORN USA in Franklin, Tennessee. "Our tools will vibrate when used in a reciprocating broaching unit, but they will not vibrate when only the machine axis is used."
At this moment, Morgan and Doosan application engineers realized that they needed to find another source for the broaching unit. Morgan sought a solution from Allen Rupert, Director of US Operations at the WTO.
Morgan and Rupert have worked together for many years on multiple projects, which led his client to receive a WTO-driven broaching unit deal from the WTO in Charlotte, North Carolina.
"We can immediately see that the device is more robust because the jitter problem we encountered at the beginning has disappeared," Morgan said. "It was decided that this was the route everyone wanted to take, so the customer immediately ordered three additional units from the WTO."
Morgan then began to find other ways to further improve his tool life.
"I discussed the application in detail with my technical engineers in Horn USA, and they helped design and develop a special broaching handle and a blade specific to the customer part drawing, which made our setup as strict as possible."
Only by increasing the neck diameter and reducing the overall length of the tool holder, the customer's tool life increased by 30%.
In addition to improving tool performance, Morgan said that the broaching department of the WTO has also improved the overall broaching process of Doosan lathes.
"They actually have a third machine, and they don't need to run it because the original two machines keep up with production," Morgan said. "WTO, HORN, and Doosan have worked together to make this project a success. Optimizing tool life is crucial, because the significant performance improvement means more money in our customers' pockets."
Workpiece material: up to 1,000N/mm2
Maximum. Feed per stroke: 0.15mm
Cutting direction: X+ or X-
Click on the link to learn more about the range of machine tools offered by Doosan Machine Tools America: https://goo.gl/h9v9DV.
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Invest in precision workpiece clamping equipment and high-performance tools, which can realize one-time processing and finishing in one setting.
New designs, technologies, and materials in the manufacture of medical equipment, appliances, and tools have increased the demand for precision workholding equipment that can meet strict product quality standards and increase production capacity.
"The medical industry poses unique challenges to the manufacturing industry," said James F. Woods, president of Hainbuch America, a North American distributor of Hainbuch GmbH in Germany. "The combination of requirements—high precision and surface finish and wide diffusion of part geometries in complex materials—needs not only precise and rigid workpiece clamping, but also allows for efficient and accurate conversion. Because even the latest machines are often equipped With traditional chucks, it is necessary for manufacturers to purchase higher-quality workpiece clamping equipment that can meet their current and future operational needs."
Highly specialized medical applications redefine accuracy and precision. In traditional machining, these traditionally refer to the ability to maintain tight tolerances. Modern demand usually involves other factors. Parts that require high finish are usually transferred from turning or machining centers to specialized grinding or polishing machines. Today, this is not practical for many reasons, including moving parts between machines which may cause inaccurate positioning. Multi-machine operations are also more expensive due to equipment costs, tools, and time required to perform the transfer. Using precision workholding equipment and high-performance tools, one machining and finishing operation can be completed in the same setup-this is an increasingly important consideration for flexible workholding, especially for orthopedic equipment.
Pete Peterson, Germantown National Sales Manager of Hainbuch America, Wisconsin, explained: “Regardless of the application, we emphasize the importance of cooperating with suppliers that provide rapid replacement of multiple sizes of chucks (chucks). Able to handle ID and OD processing at the same time. We recently assisted a factory in the production of combined cups involving multiple machine operations. By reducing the conversion time of various sizes, they maintained high precision while increasing the output by more than 40%. This not only enables Operations are more streamlined and it enables them to seek more business."
The owner of a medium-sized workshop that produces bone spicules and surgical tools explained: “When we use precision fixture equipment on all machines, we incur expenses in terms of initial expenditure and training. We know that it may not be necessary for every job. , But by equipping, we are ready for any content that the customer designs next. It also allows us to bid for more work. If you want to stay competitive in this business, this is what you have to do ——The sooner the better."
The highly competitive nature of medical manufacturing has also redefined the concept of economics and competitive advantage. This has created a management model that emphasizes both preparation and response to today’s challenges, making the flexibility of their workholding systems critical.
Matt Sacommanno's Microconic chuck holder for small parts processing was inspired by his experience in the Swiss screw machine shop.
In 1996, Matt Sacommanno, co-founder of Masa Tool, as the engineering manager of Allied Swiss Screw Products, was frustrated with the limitations of traditional chucks and workpiece clamping systems when performing secondary machining operations. This was in the early days of CNC Swiss-type machine tools. At that time, the machining capacity was limited and a lot of secondary machining was required. His solution-a high-precision collet-type workpiece clamping device for small parts processing.
As machining capabilities increase and precision requirements become more challenging, Sacommanno realized that the traditional chuck system used in micromachining is a serious limiting factor that hinders the full use of modern machine capabilities. This prompted Sacommanno to design the next-generation Microconic system.
"The Microconic system consists of a chuck and a chuck. The chuck is installed in the machine just like a standard traditional chuck," Sacommanno said. "The ink cartridge is an independent precision mechanism that uses the machine's standard chuck closing function to bring Microconic functionality to any machine."
The chuck is suitable for more and more machines, and currently it can be used for machines that use TF20, TF25 or 5C chuck. The Microconic UM10 chuck is installed in the chuck to fix the workpiece, and due to the design and closing action, it is essentially more accurate and consistent than the traditional chuck.
"The origin of the word Microconic implies the precise formation of the closed taper of the chuck to eliminate the effects of heat treatment warpage and grinding tolerances, providing concentricity every time," Sacommanno explained. "There are two basic types of Microconic chucks-standard chucks and over chucks. Both types are suitable for any of our chucks. Our over clamping chucks are rigid, concentric and open to a larger clamping diameter 4 mm (0.156 inch) capacity."
Sacomano explained that the patented design of the system can improve the over-clamping performance, which is impossible in the traditional chuck system according to his own experience.
The chuck chuck contains an ejection guide sleeve blank for ejecting the part from the chuck-this is an often challenging task, because if it is not safely guided out when opening, the parts inside the chuck The larger head may get stuck.
The Microconic system is beneficial for orthopedic bone screws, miniature precious metal components for pacemakers, and other implants; machined surgical components made from hypodermic needles; and surgical instrument components. This is an example-dental implants.
Material: Titanium alloy bar
Machine: Star SR20 Swiss-style CNC automatic lathe
Previous method: Since a strong gripping rod is required to perform a powerful blind hole hexagonal broach, the dental implant is processed almost entirely on the main shaft of the machine. There is very little work on the pickup spindle, so it is idle for most of the cycle.
Cycle time reduction: 164 seconds. To 98 seconds. Each part: By moving all ID processing operations to the picking spindle, performing these operations during the shadow time while the main spindle completes the OD, a 40% improvement has been achieved. This was previously impossible with traditional chucks because the broaching force pushes the part back into the chuck. The 0.001" concentricity requirement from ID to OD cannot be reliably achieved using traditional extended nose chucks, and they damage the critical surface finish on the implant OD.
Cost saving: productivity increased from 18pph to 32pph, saving 44% of cost. In addition, since the cut is at the other end, there is no need for manual deburring.
Return on investment: The cost of the Microconic system was recovered within 64 production hours; the direct production cost of 10,000 orders was saved by US$14,015.
Sacommanno said that the system relieves the challenges faced by machinists when setting up small parts to process by solving the limitations of traditional chuck systems.
"Because of the fast closing action, high clamping force, rigidity and accuracy, the chuck type workpiece fixture has always been the best method for clamping small workpieces in the production environment. In order to clamp various workpieces with different diameters, a specific size is pre-made Chuck to match the clamping diameter," Sacomano said. "The external dimensions and shape of the chuck have not changed, only the inner diameter of the clamping surface has changed. Therefore, the chuck system of any given machine must be large enough to accommodate the machine’s maximum workpiece diameter capacity. The result is a chuck mechanism. Designed to handle the largest workpieces, which means it is too powerful and bulky for smaller workpieces. Smaller parts will be sacrificed because they usually require higher precision and workpiece clamping is more critical. "
Prescott explained that Microconic cartridges can be optimized for small parts of the machine in three ways.
Precise control-no matter how powerful the mechanical device of the machine, the ink cartridge can provide complete internal control of the chuck closure. Using MicroGrad wrench to set the precise chuck closure micrometer adjustment, even the most fragile parts can be safely fixed without damage. The off setting can be recorded in the setting plan and repeated accurately without relying on the mechanics' feeling or experience.
Improved accessibility to parts-due to interference with the relatively large spindle nose, it is difficult for small parts to reach the part with a small tool. Traditional systems usually use an elongated nose-shaped chuck to provide sufficient clearance, which will lead to insufficient concentricity, and the bending of the jaws of the long chuck will result in poor rigidity and clamping force. The mechanic will then apply more force to hold the part firmly, which may cause damage to the part. In addition, as the force increases, the degree of curvature increases, so the jaws of the chuck begin to open outward, resulting in a decrease in the clamping strength at the end where the cutting force occurs. Unable to perform powerful machining operations, such as blind hole broaching, because the part slides in the chuck and pushes back. With Microconic, the sturdy extended nose tip of the chuck directly exerts a closing force on the workpiece. The maximum rigidity is achieved, so the parts can be firmly fixed without too much force, thereby achieving operations that cannot be performed by traditional chucks.
Quick setup-The chuck can be replaced and adjusted completely from the front of the spindle. In addition, the concentricity and rigidity mean that there is no need to troubleshoot or replace the chuck to find a working chuck. Ensure that the system does not increase the total indication jump more than 0.0002" (5µm).
When making changes to the system, the mechanic will remove the old chuck (and spring, if any) and install the Microconic cartridge in the same way as the old chuck. The Microconic chuck is then threaded in from the front of the chuck, which makes the chuck replacement easier.
When installing the ink cartridge for the first time, the mechanic should use a dial indicator to measure the jitter of the front end of the ink cartridge, which is ground to a tolerance similar to that of a measuring tool.
"If there is any runout, this is the result of the condition of the machine shaft and should be diagnosed as needed. Usually this is just a very thorough cleaning of the valve seat surface, but it may also be due to production wear or damage," Prescott pointed out . "The key here is to correctly diagnose and correct concentricity problems right away without running parts or trying multiple chucks. Once corrected, concentricity will be fine every time, saving hours of troubleshooting in future settings time."
About the author: Elizabeth Modic is the editor of Today's Medical Developments and can be reached at emdic@gie.net or 216.393.0264.
Microconic's filter element is made of peculiar high chromium tool steel, which has undergone three tempering and low temperature treatment to provide a stable structure. All functional seat surfaces have been polished extremely accurately on the one-piece super-rigid body structure.
"The cartridge can be used as a calibration gauge to verify the accuracy of the machine spindle," said co-owner Chip Prescott.
The Microconic chuck is finished according to strict standards through a five-step grinding process, eliminating the effect of heat treatment warpage. In addition, the proprietary Microconic form of the closed surface is inherently more accurate than traditional chucks, providing a larger full-precision working range.
Cartridges suitable for push-in fixed-length chuck closers and pull-out closers are available: F20M10 (used to replace TF20 chuck), F25M10 (used to replace TF25 chuck) and 5CM10 (used to replace 5C chuck) ). All these cartridges use the same Microconic UM10 chuck, and more cartridge sizes are under development and will be released soon.
For many medical device manufacturers, proprietary coatings and surface treatments can play an important role in product development.
Silica or silicon dioxide is one of the most basic elements on the earth. The most common in nature is quartz, which is the main component of sand, as well as silicone and glass. Now, this basic compound is using plasma-enhanced chemical vapor deposition (PECVD) technology as an antibacterial barrier, primer to promote adhesion between stainless steel and proprietary coatings, or to create hydrophobic or hydrophilic surfaces.
For many medical device manufacturers, proprietary coatings and surface treatments can play an important role in product development and upgrading of traditional medical devices under the 510(k) guidelines. Therefore, the medical device industry is actively researching plasma coatings and applying them to products such as stainless steel guide wires, catheters, stents, and vascular surgery tools.
"We are always looking for unique and novel ways to make our products stronger and become market leaders, but to do this, we need to bring more technology to our equipment. Usually, this will involve some form of To functionalize the surface,” MicroVention’s R&D project team leader Aaron Baldwin explained. MicroVention is a company that provides neurointerventional products, including access products, endoluminal stents, occlusion balloons and polymer coils.
"By solving surface reaction issues such as biocompatibility or lubricity, PECVD can take the product to a new level. This is a unique and effective method of depositing and enhancing coatings because it allows you to customize the surface while preserving your The characteristics of the bulk material required."
The PECVD process deposits thin films from gaseous (vapor) to solid on the substrate. PECVD deposition of silicon dioxide usually requires organic silicon as a raw material. In this family, the most famous are hexamethyldisiloxane (HMDSO) and tetramethyldisiloxane (TMDSO).
HMDSO is an economical and flexible reagent that can be bought on the market as a high-purity liquid. This volatile, colorless liquid can be polymerized by plasma to form a safe surface coating for various medical purposes. Depending on the composition of oxygen to HMDSO, the nature of the surface can be either hydrophobic or hydrophilic.
This flexibility makes HMDSO and other siloxanes ideal for PECVD. By adjusting the parameters and adding other gases, chemists can strictly control the materials to cope with a wide range of applications.
For the medical device industry, the use of silicone belongs to the main categories of protective barriers (antibacterial, anti-fungal, anti-corrosion), as a primer between stainless steel and rare metals and proprietary surface coatings, or to modify the surface to hydrophobic or Hydrophilic.
For metal substrates such as stainless steel or special alloys, it can be difficult to adhere the coating to the surface. Hexamethyldisiloxane (HMDSO) can be used as an intermediate layer to improve the adhesion between the coating and the substrate.
For example, stainless steel guide wires are usually coated to make them smoother and easier to insert. By applying a thin layer of silicon dioxide, the lubricating coating can be grafted onto the stainless steel surface well.
Silicones can also be used as bonding chemicals between other difficult-to-adhere surfaces, such as ceramics and polytetrafluoroethylene (PTFE Teflon). Drug delivery devices that use ceramic nozzles with micrometer-sized openings are coated with PTFE to prevent clogging. Depositing a layer of HMDSO with a thickness of 100 nm to 150 nm can promote the bonding between the two substances.
In order to protect electronic products, HMDSO coating is applied in a relatively thick coating of a micrometer or more. HDMSO is waterproof and gas-proof-the properties needed to prevent corrosion. If the HMDSO will be exposed to harsh chemical acids or bases, a thin layer of PTFE (~100nm) can also be applied.
For vascular surgery tools and instruments that are contaminated by tissue fragments or blood, the coating can make the surgeon's tools cleaner and longer.
Applying a hydrophobic (waterproof) coating on surgical instruments will form a surface where blood and tissue can easily fall off, providing surgeons with a better view.
At the other end of the spectrum is a hydrophilic (affinity with water) device. Depending on the needs, silicones can be used to create such surfaces with polar or dispersive surface energy.
There are many strategies to achieve antimicrobial surfaces, including cell harpoons, amphiphilic surfaces, preservatives that bind to the surface, and non-stick coatings.
In a unique application, chemical vapor deposition is used to embed nano-silver particles in a thin layer of silicone to prevent microbial adhesion and corrosion. Silver ions can be embedded in a thin layer of silica to kill any bacteria that are present.
Although the application of PECVD silicones is flexible, the development of precise chemical, gas and plasma equipment design requires close collaboration between medical equipment designers and equipment manufacturers.
Because MicroVention has established a relationship with PVA TePla-several of its plasma chambers have been used to help the coating adhere-Baldwin began to negotiate with them on a project to determine the benefits of stent coating.
Baldwin said that plasma equipment manufacturers are divided into two categories, one is to produce goods, off-the-shelf products, and the other is to design and design systems to meet the needs of specific applications and/or solve unique surface energy challenges. Therefore, when companies pose challenging surface chemistry issues to PVA TePla, they will be encouraged to visit the laboratory in Corona, California, giving them the opportunity to brainstorm and conduct experiments with their technical team.
Many of the best experimental matrices and ideas were generated during these technical customer/supplier meetings. In addition to designing and manufacturing plasma systems, the company also acts as a contract manufacturer, owning the internal equipment needed to run parts and conduct experiments, and allow customers to fully participate.
"When we start to do something new, instead of groping in the dark, it is better to involve expertise. [PVA TePla] is very willing to experiment-usually for free-to promote the project and improve its characteristics. Systems and chemicals," Baldwin said. "We were able to go there and use their plasma machine to determine our parameters and evaluate the equipment."
Each PVA TePla system is designed to meet application requirements, which can include unique fixtures, unique electrodes and chamber modifications to accommodate throughput and coating uniformity.
The ability to thoroughly clean the chamber after each application of silicone is a major consideration, because in addition to the product that receives the coating, it also coats the entire interior of the chamber (including the electrodes). Therefore, PVA TePla has modified the chamber to make it easier for users to clean it after each coating application.