While choosing the right implant material is of utmost importance, as discussed in our previous Orthopedic Implant Series post, the significance of optimum surface treatment throughout the entire implant manufacturing process cannot be overstated. This relates not only to the right surface finish, but also total compliance with the specified tight dimensional tolerances.
The functionality of an orthopedic implant is determined by the perfect match between the various implant components. This depends, to a large extent, on the surface treatment procedure(s).
Andersen Steel produces agricultural equipment including grubbers, front packers, and stubble tillers equipped with vibration tines for soil cultivation. Their equipment is exposed to extreme loads, causing decreased wear life of parts including the tines.
Made using specially arched rolled steel at the company’s Poland plant, Andersen Steel tasked engineers at Rosler with finding a better way to process the tines and improve their wear life. We delivered a solution in the form of two identical machines for blast cleaning and shot peening.
Delivering a Solution
Compared to flat steel, the rounded edges of the material Andersen uses prevent small cracks from forming during the shaping process. The work pieces pass through a blast machine to remove mill scale and other contaminants before shot peening to further improve their wear resistance.
For these dual shot blasting requirements, Rosler suggested two identical Rosler RHBD 13/18 K hanger machines. Successful blasting trials in a Rosler test center helped Andersen realize the advantages of purchasing these Rosler machines by demonstrating that shot peening the work pieces doubled the uptime of the tines.
Critical aerospace components require first-class surface treatment. From engines, fuselage, wings, and landing gear to seats, gears, propellers, blades, fasteners and tanks for fuel, water, and waste, Rosler has industry experience and expertise.
While mass finishing and shot blasting methods are equally useful to manufacturers of new components and in the overhaul and repair of existing components, shot peening – a particular type of shot blasting – is especially advantageous for aerospace work pieces thanks to its ability to provide surface finishing and create internal compressive stress for improved component life.
Shot Blasting Capabilities
Rosler’s shot blasting technology meets the strict surface finishing requirements predicated by tight tolerances for safety and longevity. This impact-based process propels small metal or mineral pellets onto a work surface at speeds of 200-800 feet per second.
Desired finishes including cleaning, texturing, removal of or preparation for coating, and peening can be pinpointed to specific areas of a given work piece as well as the entirety of large, structural components.
For transmission components like gears and shafts, shot peening has become an indispensable step in the overall manufacturing process.
With the RWT swing table machine, Rosler developed a modular equipment concept that can be easily adapted to different technical requirements and offers a maximum in process stability paired with absolutely repeatable peening results and high cost efficiency. One of the numerous customers within the automotive industry utilizing the RWT is an Asian automotive supplier.
As part of a capacity expansion for minivan transmissions, this customer increased annual production to 40,000 units and decided to carry out the required shot peening operation in-house instead of subcontracting it to an external job shop.
The specifications called for a system that can handle around 560,000 single work pieces per year, including 15 different types of gears and shafts. Each work piece type required the development of a specific peening program based on drawings and various work piece materials.
It’s hard to dispute that technology, on the whole, has made our lives easier and more convenient. Myriad functions have been automated – and improved – to mitigate the effects of human intervention. We make purchases more intelligently, we manage data more efficiently, we can control devices with our voices and eye movements, and we ultimately move through life with less left to chance.
In the world of manufacturing, this mitigation of human intervention promises even greater and more measurable, efficiencies. At Rosler Metal Finishing, quality improvements and cost benefits that have resulted from the mechanization and automation of mass finishing and shot blasting operations deliver dividends that transcend the manufacturing floor.
Since the first microprocessor-controlled machine appeared
on the manufacturing floor in 1974, hundreds of new varieties have been shipped
across the world. With each improvement, these automated attendants encompass a
larger footprint, are able to handle heavier loads and more axes, and require
fewer controllers to do their work, according
to a McKinsey study.
Automation has revolutionized smaller tasks as well,
including simple parts bin handling, lift assists, automatic media adding
systems, or multi-step process control systems (like those where noxious
chemicals are dosed, without human risk, into the process).
So how do these automation
upgrades pay off for you? Let’s start by taking a look at where mass finishing
and shot blasting has fit into the manufacturing paradigm. Then we’ll dive
deeper into the benefits of today’s automated processes which have a lasting
impact on the finished product.
High speed and highly controlled, the process of shot peening has many similarities to the aerospace, automotive, and aviation components it is used on. The machines require absolute precision and reproducibility much like the components they are preparing for long life and changing loads.
Shot peening is a special shot blasting process in which spherical blast media is thrown at the surface of metallic work pieces. The impact energy of the pellets “cold forms” the upper layers of the metal similar to hammering and forging processes.
People associate shot peeningwith automotive and aerospace components. However, did you know it’s used in the medical implant and component industry. Bone screws, dental implants, and hip and knee replacement components are just a few of the medical implants that are shot peened.
Imperial Ksi means kilopound per square unit and is derived from psi(lbs/square inch). Kilo, which is often used in the metric system basically means a thousand (1000). It comes from the Greek word for 1000. Therefore, a kilopound is 1000 pounds.
Metric A Megapascal (or MPa) is a variation on a pascal. Mega in this case means 1,000,000 and again it means “great”. As you may guess, when using MPa you are usually working with something heavy or with a high pressure!
Both ksi (kilopound per square inch) and megapascal (MPa) are units of pressure measurement – the former is an Imperial unit of measurement and the latter a metric unit. Ksi values are commonly converted to MPa, as the metric system is the more widely used system of measurement.