Considering that automotive crankshafts weigh around
40-60 pounds and rotate approximately 100 times per second, these parts are
exposed to tremendous tensile, compressive, and shear stresses. In addition,
combustion forces and piston acceleration in an engine can also cause
Therefore, crankshafts must be made from tough,
wear-resistant materials, usually high alloy carbon steel. Typical alloying
elements are manganese, chromium, molybdenum, nickel, cobalt, or vanadium.
worldwide sales at nearly $10 billion annually, there is a high demand for
spinal implants. These implants are subject to very specific and strict surface
finishing requirements to ensure longevity and fixation to bone.
Mass finishing and shot blasting play key roles in creating the right finish for spinal implants, not only for intermediate surface treatment after forging, casting, machining, additive manufacturing, etc., but also for placing the final surface finish before implantation.
process to meet increased production demand is a cost-effective way to not only
improve your processing times and results, but also increase and prolong your
Let’s say production
has been steadily building over time. How do you know if it’s time to evaluate
the process for improvement?
Mass finishing experts suggest examining the final finish accomplished by the process and its ceramic or plastic media and compound usage. Processes in need of optimization will not achieve the desired finish in an acceptable timeframe and will use more media and compounds than necessary.
Characterized by its sturdy design and numerous technical features, Rosler Metal Finishing’s drag finishing systems are ideal for high value and sensitive parts such as aerospace components that cannot touch each other during the finishing process.
Equipped with a rotary carousel featuring 2 to 12 spindles to mount the parts, work pieces are “dragged” through the media mass. The rotation of both the carousel and the spindles guarantee an even treatment of the parts. Drag finishing offers a metal removal rate that is up to 40 times higher than conventional vibratory finishing.
To this day, the surface of large structural
aircraft components is frequently finished by hand. This process is not only
costly, but extremely inefficient and hard to replicate with absolute
Rosler Metal Finishing is changing the notion that suitable mechanical finishing equipment is not available for large, structural aerospace components by offering mass finishing technology capable of solving this problem and providing fully automatic finishing of work pieces up to 30 feet long.
We kick off our Aerospace Series with an overview
of the cost-effective and mechanical finishing options Rosler offers for the
Vibratory Tubs Offer a
Thanks to the development of large, powerful vibratory tubs manual deburring and grinding of large aircraft components can now be eliminated. The development of perfectly controlled mechanical finishing systems offers finishing solutions for applications where the biggest rotary vibrator, because of the size of the parts, might still be too small.
Mass finishing is a highly versatile finishing technology that can be used for a wide variety of different surface treatment operations including those in the medical industry. Therefore, it is no surprise that mass finishing processes are utilized at practically every manufacturing stage for all kinds of orthopedic implants.
Rosler Metal Finishing has decades of experience in mass finishing. In this installment of the Joint Reconstruction Series, we will compare the various machines used to provide precise finishing for endoprosthetic manufacturers.
Examples ofMass Finishing
Mass finishing is used for a variety of joint
replacement work pieces including:
Descaling and edge radiusing of hip stems, knee femorals, and other
implants after forging or casting, e.g. lost wax or investment casting.
Deburring and surface smoothing of various implants after belt or CNC
Final polishing of knee femorals, femoral heads, and the inside of
acetabular cups to Ra = 0.8 micro inches as the last finishing stage before
Shot blasting and mass finishing have become indispensable technologies for surface preparation and finishing of joint reconstruction implants. Their applications range from surface cleaning, deburring, edge radiusing after forging, casting, additive manufacturing, and machining to surface preparation for different kinds of coatings, shot peening for increasing the longevity of an implant, and placing an extremely smooth, high-gloss finish on the implants before they are inserted into the body.
Joint reconstruction implants allow millions of
individuals to regain mobility and reduce pain. Just as surgical skill is
required to implant these artificial joints, so is skillful construction and
finish of the joint components themselves.
Our Joint Reconstruction Series continues with an
overview of the most common materials used for these endoprosthetic implants.
The most common materials used for joint reconstruction implants are currently titanium and titanium alloys and cobalt-chromium alloys. Both materials are very tough, corrosion-resistant, highly biocompatible, and have proven themselves to be absolutely reliable.
Getting castings and forgings ready for the subsequent processing steps presents some of the toughest surface finishing challenges. Shot blasting machines can handle all of these tasks from removing residual sand, casting shells, flashing, die marks, or scale. Whether cast iron, steel, stainless steel, super alloys, titanium, aluminum, zinc, or magnesium, the comprehensive portfolio of Rosler Metal Finishing blasting systems for the foundry industry enables the optimal process for any requirement.
Shot blasting is an essential part of most forge
and foundry operations and has been used since the late 1800s. This specialized
surface finishing process throws small metal (or mineral) pellets, called blast
media, onto the surface of a work piece at incredibly high speeds, ranging from
200-800 feet per second. The impact on the work pieces from this process is
what blasts the contaminants from the parts and produces the desired surface
When properly applied prior to finishing, blasting
achieves three key aspects of the finishing process:
Cleans and descales
Creates a uniform
texture on the part and blends the surface
Along with the material choice discussed in Part 1 of our Spinal Implants series, surface treatment is the most important factor affecting the functionality, performance, and longevity of spinal implants and instruments.
During the manufacturing process they may have to undergo multiple
finishing operations including burr removal from previous manufacturing
operations, rounding of sharp edges, general surface cleaning, surface
smoothing, and, frequently, high gloss polishing.
Treatment steps can also include surface texturing/profiling and shot peening, areas Rosler Metal Finishing has extensive experience in.
This blog post will focus on the finishing requirements and challenges
of spinal implants as well as the solutions provided by mass finishing and shot
blasting processes and the associated costs.