Using Swiss-type Machines to Manufacture Medical Components

The latest machining technology should be used in your warehouses and workshops to accurately create medical components.  Swiss-style lathes are a great combination of precision and repeatability due to their guide-bushing design, which provides support for the workpieces very close to the cut. Most businesses recognize that the US medical market offers more opportunities for those that create intricate components from tough materials. 

The United States has the largest and most sophisticated medical market in the world.  This is due to the aging population.  There are 35 million people 65 and older but by 2075 there will be about 69 million in the senior age group.  The rising cost of healthcare is another reason why the medical field is a new-business venture for many manufacturers.  Insurers and healthcare providers are creating pressure to reduce costs by increasing manufacturing productivity, which gives shops the opportunity to be capable to machine medical parts and devices in an efficient matter. 

Adopting the latest machining technologies becomes key for shops to accurately and repeatably create medical components.  The need for more sophisticated machining practices is driven by difficult materials, shrinking component sizes and the complex operations needed to create tight-tolerance features on these parts.  Swiss-style lathes offer a good combination of precision and repeatability for these applications due to their guide-bushing design, which provides support for the workpieces very close to the cut.

Many different areas and departments in the medical field can be served by shops using Swiss-type turning.  Some of these include interventional cardiology devices (stents, catheters and surgical tools); orthopedic devices (bone screws. implants and joint replacement); minimally invasive surgical equipment (laparoscopic devices); diagnostics (point of care testing instruments); wound care (staples, suture anchors and clips); and dental implants and equipment. 

Here are some tips for producing common medical component features and equipment on Swiss-type lathes:

Micro-machining is machining on a small scale that requires a proper mindset in terms of part handling, tool handling, inspection and secondary operations.  However, it starts with machine accuracy because even the best tooling won’t help if the machine lacks positioning accuracy.  Runout that might be acceptable for a standard-size part likely isn’t acceptable when machining features on tiny parts.  High precision collets are used for the machine’s main spindle, pickoff device and guide bushing.  High-frequency spindles are essential for drilling and milling tiny features into parts while achieving the desired surface finish, accuracy and tool life. 

When performing internal broaching, it is important to use the proper broaching tools and to prepare the workpiece for the operation.  Internal broaching requires creating a pilot hole with a 90 degree chamfer which prevents the broach’s points from chipping upon entering the cut and allows the broach to follow the centerline.  It may be necessary to remove material for the feature’s corners with a small end mill.  Deburring passes may also be required depending on the size of the chips. 

Wobble or rotary broaching uses a tool with a shape that’s similar to the final feature shape, except that it has a clearance ground into it.  The tool axis is typically inclines 1 degree from the workplace access and as the broach rotates, it presses against the workpiece. The 1 degree incline causes the leading edge of the tool to “wobble” with respect to the workpiece.  If the tool is inclined by 1 degree, the sides of the tool must have a clearance angle of at least 1 degree since the tool advances at the same rate it cuts. Wobble broaches do not cut as accurately as a punch broach, so their use should be determined by the application it will be used for. 

Thread whirling is often used to cut special form threads in difficult to machine materials and is not as limiting as other threading operations.  Thread whirling is typically used for bone screws that have a significant length to diameter ratio; deep, high-helix buttress threat forms and extreme differences between major and minor diameters.  ID thread whirling is effective for producing clean, burr-free thread contours with no residual chips and it enables threading down to the bottom of a hole to sizes as small as 0.0551 inch.  An alternative to thread whirling includes a die head (not to be used on materials such as titanium), thread milling (requires pre-turning, special cutters and special supports in certain cases), single point turning (used for short screws since long screws need support), thread rolling (requires accurate pre-turning and doesn’t work on buttress-style threads in hard materials) and grinding, which can’t be performed on a Swiss-type lathe.

Cannulated bone screws, (screws that are hollow) have a space that allows bone marrow to grow.  This also facilitates the insertion of guide pins for bone screws used in fracture fixation.  The demand for cannulated bone screws is increasing even though it can be expensive.  Gundrilling allows shops to machine these screws effectively from solid bar stock.  It offers high drilling quality, process reliability, effective chip removal, minimal runout and significant length to diameter ratios. 

If you are interested in manufacturing high quality components for the Medical Industry contact us today

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