Growing utilization of additive manufacturing for volume production of plastic components has increased the demand for cost-efficiency and high-quality surface finishes. That’s why AM Solutions, a brand of the Rosler Group, has further expanded its product portfolio with the development of a new media type for post processing of plastic components.
Designed specifically for work pieces printed with MJF and SLS powder-bed-based technology, AM Solutions’ new media permits the safe, cost-efficient finishing of 3D printed components with different shapes and sizes in one single process step and with absolutely repeatable results. This eliminates the time-consuming and costly media changes for different processing stages.
In combination with an understanding of respective printing processes, the new media mix generates a perfect, finely structured, and highly homogeneous surface finish.
Blast cleaning is uniquely capable and efficient at delivering the pre-coating surface preparation required for components that must be able to withstand severe ambient conditions including heavy equipment for construction and mining, agricultural machinery, transportation and material handling equipment, and railway equipment and rolling stock.
Based in Enschede, Netherlands, the company designs and produces numerous products including placement systems for container pads. Its customers largely work within the material handling, offshore, and transportation sectors.
Even if the finishing media and compound/water are managed perfectly, without a well-functioning machine a mass finishing process is doomed to fail. Focusing on a few essentials will ensure that a mass finishing machine is performing as intended.
From machine settings to preventative maintenance and troubleshooting tips, Rosler has the experience and insight to keep mass finishing machines running efficiently.
The Right Machine Settings
The speed at which a machine is running is critical to the success of a finishing process.
If the machine is running too fast, the work pieces may be damaged by scratching, nicking, or bending. Excessive speeds will also cause the media to wear much faster without the benefit of shorter cycle times. Beyond speed, other machine settings must be taken into consideration based on the specific machine type.
Like mass finishing, shot blasting is an exceptionally versatile surface treatment technology. Its applications range from general cleaning after casting and forging to shot peening and, even, cosmetic blasting for placing a fine, matte finish on the work pieces.
For shot blasting orthopedic implants, Rosler recommends mainly air and occasionally wet blasting systems. In each process, blast media is accelerated by compressed air and thrown at the work pieces through a blast nozzle, creating an extremely precise blast pattern compared to turbine blasting. Another advantage of air blasting is that it can be used with metallic, mineral as well as organic blast media.
These attributes and many more make this surface finishing method particularly useful in the medical industry.
Examples of Shot Blasting
Shot blasting is an impact system in which small metal or mineral pellets are thrown onto the surface of a work piece at speeds of 200-800 feet/second. The impact on the work piece surface produces the desired cleaning, peening, or texturing effect.
For medical applications, mainly air and wet blast systems are used which generally make a surface rougher. The smoothest finishes achieved with shot blasting are about Ra = 16-32 microinches (= 0.4 to 0.8 μm).
Unlike dry blasting that only uses a solid abrasive media, wet blasting processes use a slurry of water with the shot blasting media. This greatly cushions the impact energy on the work pieces, providing gentler, yet effective results for delicate work pieces. The achieved surface finish and appearance will also differ between wet and dry processes, even when the same media type and size are used.
With more than 80 years of experience worldwide, Rosler can supply both the machines and media best suited for your wet blasting needs.
Common Media Types
As long as it is heavier than water and not water soluble, practically any media used for dry blasting can be used for wet blasting.
It is important to consider the usefulness of the media compared to its cost. While a cheaper or longer-lasting media may be available, it may also require additional processing time to accomplish the desired surface finishing. Selecting the most appropriate media for your process requires balancing initial costs with overall results.
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. As a result, it is no surprise that mass finishing processes are utilized at practically every manufacturing stage for all kinds of orthopedic implants.
With decades of experience, Rosler leverages mass finishing technology and develops equipment to meet the tight tolerances required for orthopedic implants.
Common Finishing Processes
Mass finishing is a grinding system, utilizing the pressure between the media and work pieces, combined with the constant “rubbing” of the media against the work pieces. This generates a grinding and polishing effect, leaving a smooth surface finish that can be as low as Ra = 0.8 microinches (0.02 μm).
For the comfort of patients and effectiveness of the components, orthopedic implants must be finished to precise specifications.
While highly effective in a number of applications and industries, wet blasting can be a messy process. Unlike dry shot blasting which produces dust, wet blasting generates a mix of media, dirt, and debris mixed with water mist.
If this water/particle mix is not removed properly the machine itself may be soiled to the point that it cannot be used. Mist which escapes the machine can also cause health hazards to personnel and other equipment in the area.
Rosler builds its wet blasting machines with usability and safety in mind, factoring in precautions and cleaning functions to prolong the machine’s use and ensuring a clean, safe work environment.
True to our “finding a better way…” motto, Rosler partnered with thyssenkrupp AG to create a continuous flow shot blasting operation for the fastest crankshaft forge shop in the world.
World renowned for its drive trains, chassis, and automobile manufacturing equipment, the automotive division of thyssenkrupp AG significantly contributes to the technical progress and efficiency of motor vehicles. The thyssenkrupp Gerlach GmbH plant in Homburg, Germany, is a leading partner for the development of automobile engine components, offering a full-service package ranging from component design, prototype fabrication, and full-scale production.
Developing a Solution
To improve cost efficiency at its Homburg plant and to meet all customer requirements, thyssenkrupp AG installed its high-tech “production line 19” for forged crankshafts for engines with one to four cylinders in 2016. For this line, Rosler developed an innovative shot blast equipment concept known as the Rosler RKWS crankshaft shot blasting system.
Numerous functions and calibrations factor into developing a precise and stable mass finishing process. From media and compounds to work piece characteristics and processing times, successful finishing requires each process aspect to be carefully monitored and evaluated. When it comes to process water flow rates, poor drainage from the machine can cause quality control issues as well as equipment damage and costly downtime.
While simple in their function, drains play an integral role in regulating the flow of process water out of the machine. With the exception of intentional “flooding” of the process bowl for sharp work pieces, the same amount of compound and water entering the machine must be flushed out again. Otherwise, contaminants in the form of dirt, media, metal fines, and, frequently, oil will accumulate in the process water. Since this buildup can cause the finishing process to deteriorate and even collapse, mass finishing machines must have sufficient drainage!
With more than 80 years of experience, Rosler can expertly design mass finishing technology and troubleshoot issues to protect your system for the life of the machine.
Made from plastic such as polyurethane or stainless steel material, these drains must allow process water and media debris to be flushed from the system while retaining usable media mix and the work pieces.