Modern metal fabrication operations aren’t like the fab shops of old. Many are clean, well lit, with employees working in fresh, filtered air. Yes, some operations in fabrication are, well, just plain dirty—and manual blasting is a prime example. The work isn’t pleasant, requires protective gear, and if the booths aren’t maintained or set up properly, they can constrain workflow in a serious way.
Options in blasting automation abound, but before diving into all that technological wizardry, try laying some groundwork by answering a fundamental question: What must the blasting operation accomplish?
Shot Blasting Versus Shot Peening
Shot blasting (or just “blasting” if using a different media other than shot) prepares a metal surface while shot peening aims to change the metal’s properties (see Figure 1). Certain aerospace applications require precise levels of stress relief (or other changes to material properties), and they use specialized shot-peening technologies to achieve it. Precision shot peening of landing gears is a prime example, with the process optimizing surface stresses, eliminating microcracks and the stress risers around them.
Most metal fabricators employ blast cleaning for the vast majority of their applications, cleaning and preparing a metal surface for the next manufacturing step, usually painting. If a beam or plate isn’t blasted correctly, paint won’t adhere properly. However, some fabrication operations do employ a kind of peening—not as precise as high-end peening applications, but it’s peening nonetheless, with the media impacting the surface and causing compressive stresses that aim to change the material’s properties.
For nearly a decade, Sales Representative and Interim Product Manager of Turbine Blast Equipment Zack Murray has been one of Rosler’s top shot blasting experts.
Working with customers and our global Customer Experience Centers, he helps develop and test surface finishing machines and media in addition to dialing in specific process parameters.
At times, adhering to the Rosler motto and guiding principle of “finding a better way…” can be difficult and complicated. Luckily, Murray and the entire Rosler team are committed to delivering world-class surface finishing equipment, consumables, and service in a variety of industries.
In this post, Murray shares the most challenging issue he has tackled at Rosler and how the team developed a solution.
A member of the Hager Group since 2010, Berker is one of the leading manufacturers of high-end electrical components, from timeless classical switches to intelligent electrical systems for buildings. The company also supplies switches for electrical appliances and automobiles.
Berker primarily uses continuous feed systems such as loop and flat belt machines to deflash plastic components including switching elements, electrical outlet covers, frames, and more.
Increased production volume at its Wenden-Ottfingen manufacturing location led Berker to decide to invest in an additional shot blast machine in 2018. The new investment was intended to replace an existing continuous feed loop belt system with the latest deflashing technology.
Its specifications called for increased capacity and high equipment availability.
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.