Our Forge and Foundry Series continues with a look at the cleaning required for sand castings and the collection of removed contaminants.
Rosler Metal Finishing builds shot blasting machines that are equipped to prepare the surface of sand castings as well as collect removed contaminants for a consistent workpiece finish and the health of the utilized machine and personnel.
What design features must be considered in blast turbines used for the cleaning of sand castings?
Baked-on molding sand, sand cores, and scale/rust on the sand castings are difficult to remove and require turbines with a lot of fire power. Turbines with curved throwing blades, such as Rosler’s Gamma G series, have proven to be exceptionally effective since, compared to straight-bladed turbines, the curvature of the blades generates up to 25 percent higher throwing speeds!
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.
Building upon the information shared in our last Forge and Foundry Series post about sand casting, we now turn to the process of selecting and designing machines to specific sand casting operations.
Selecting the right shot blasting machine for your process and work piece means understanding how the work pieces and machine will interact. Here are common questions Rosler Metal Finishing receives when developing perfectly specified solutions for sand casting.
How do work piece
delicacy, size, and weight influence the machine choice?
Before choosing a machine, the following questions
must be asked:
Are the parts sturdy, allowing for aggressive processing, or must they be handled gently, without any part-on-part contact?
Is batch processing possible or must it be continuous?
Which work piece handling system is best: rotary drum, troughed belt, wire mesh belt, overhead monorail system, or heavy-duty crane or trolley on rails for extremely heavy work pieces weighing several tons?
Can the work pieces be handled by robot or is a custom-engineered shot blast system the best solution?
It is extremely important to find a supplier that
can offer a machine that is perfectly matched to the work piece
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
When it comes to shot blasting complex weldments
like the chassis for construction equipment, excavator booms, and wind power
components, sometimes even the best turbine placement may not clean all the
nooks and crannies of the work piece’s surface.
Surface finishing experts such as Rosler Metal Finishing have solved this issue with the addition of manual blast rooms to automatic shot blast systems.
This installment of our Structural Steel FAQ
series will answer When are blast rooms behind turbine blast machines required for manual
shot blasting, structural steel components often require some cleaning. The
degree of cleaning depends on the work piece’s condition prior to processing as
well as machine set-up.
This installment of our Structural Steel FAQ series will answer How are residual blast media and dust removed from shot blasted steel components?
Why Remove Residue
Ancillary machine attachments and processes may be
required to remove blast media and dust resting on structural steel components
to ensure surfaces are properly prepared for painting and coating.
The need for a clean and well-prepared surface after shot blasting mirrors that of the pieces surfacing in the first place as discussed in Part 1 of this series.
Practically all plate and profile roller conveyor
shot blast machines are equipped with a media brush-off system at the machine
exit. By adding a rotary brush at the end of the process, residue is removed as
the work piece exits the machine.
Shot blasting machines are widely used for surface preparation and finishing structural steel components for a variety of industries. In addition to specifically designing machines able to accommodate large, heavy, and bulky structural steel workpieces, Rosler Metal Finishing also expertly designs the turbines within these machines for precise results.
turbines accelerate and throw the blast media against the workpieces. They are
for shot blast machines what the engines are for cars and trucks. Both
determine the performance of the respective machine or vehicle including the
speed of a sports car and the torque of a heavy-duty truck.
Like vehicle engines, the specifications of different turbines directly influence the performance of a shot blasting operation. This installment of our Structural Steel FAQ series will answer How do different blast turbines affect the quality of shot blasting results?
patterns are the size and shape of the area where blast media strikes a
workpiece as it progresses through the machine. The area of impact is also
referred to as a “hot spot.” Long blast patterns are required to accommodate the
large size of structural workpieces.
Concentrated blast patterns are often used in shot peening, but would not offer enough finishing coverage for structural steel applications. Similarly, the normal blast patterns used for casting and forgings are also not effective for structural steel.
Rosler Metal Finishing expertly designs shot blasting machines for these industriesand others to descale, clean, and prepare structural steel for surfaces for end-use. The particulars of each machine largely depend on the size and shape of the specific components in need of preparation.
This installment of our Structural Steel FAQ series will answer What are the most commonly used blast machines for structural steel surface preparation and how do they compare?
Machine Types by Workpiece
Whether surface preparation is needed for steel beams and plates, round bars, pipes and weldments, ship building, pipeline construction, or heavy equipment and machinery, there are machines tailored to produce consistent surface finishing results for each component.
The most common machine types by component include:
Roller Conveyor Machines for Plates and Beams
Round Bar and Pipe Machines
Roller Conveyor Machines for Large, Extra Heavy Components
Spinner Hanger and Monorail Hanger Machines for Large Components
The surface profile created by shot blasting depends entirely on the blast media and the way it is handled. The right media selection and equipment operating parameters are critical for the surface quality of structural steel components being prepared for paint coating. While mineral abrasives play a role for certain air blast applications, the lion’s share of industrial surface preparation is done in highly mechanized turbine blast machines utilizing steel media.
Rosler Metal Finishinghas decades of experience in the turbine blasting field. Through the years, we’ve used and evaluated all kinds of media and resulting roughness or lack thereof. This installment of our Structural Steel FAQ series will answer:
What influence does metallic blast media have on the surface profile
of structural steel?
Besides the degree of cleanliness – the removal of oil and grease, rust and mill scale, dust, and other contaminants – surface preparation specifications must also consider the surface profile and roughness relative to the coating to be applied. Rosler Metal Finishing builds shot blasting equipment to create the right surface profile on structural steel components as well as cleaning them in preparation for coating and painting.
This installment of our Structural Steel FAQ series will answer What is the optimum the surface profile for a structural steel component prior to painting and how is profile evaluated?
Optimizing for Painting
Shot blasting makes a surface rougher to increase the total contact area between paint and a work piece substrate and generally improves paint adhesion. A surface that is too smooth poses the risk of inadequate paint adhesion, while a surface that is too rough may not cover the peaks. The degree of surface profile required depends entirely on the coating to be applied.