Category Archives: Forge & Foundry

Forge & Foundry, Part 5 – Cleaning Features & Dust Precautions for Sand Castings

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!

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Forge & Foundry, Part 4 – Selecting a Shot Blast Machine for Sand Castings

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 characteristics.

Continue reading Forge & Foundry, Part 4 – Selecting a Shot Blast Machine for Sand Castings

Forge & Foundry, Part 3 – Shot Blasting & Sand Castings

Our Forge and Foundry Series continues with a deeper look at sand castings. While more than 60 percent of all metal castings are made with a sand casting process, the specific shot blasting machines used to remove surface contaminants vary. Rosler Metal Finishing is uniquely qualified to identify the right shot blasting machine for your process and can help determine what settings and media will produce the best results with every cycle.

Sand Casting Basics

Sand casting, also known as sand molded casting, is a metal casting process using different kinds of sand as mold material. The sand is usually “glued” together with a bonding agent like clay, water, oil, resin, or sodium silicate.

A sand mold consists of two or more sections. Liquid metal is poured into the cavities formed by the mold.

Once cooled, sand molds pass through a shakeout device, where they are destroyed to extract the metal castings. The raw castings then undergo a fettling procedure, where sprews, gates, runners, and risers are separated, and coarse burs are removed.

Continue reading Forge & Foundry, Part 3 – Shot Blasting & Sand Castings

Forge & Foundry, Part 2 – Efficient Recycling

When a casting is produced, by-products are generated. Small pieces originating from spills, gates, runners, and risers are returned to the casting process as recycling material. To ensure a consistently high overall quality of the raw material, it is essential that this recycling material is perfectly clean without any sand, casting shell, or other residues on the surface.

Subjecting these by-products to a blast cleaning process from Rosler Metal Finishing before they are re-melted offers many advantages. Besides the resource-saving use of raw materials, the effective cleaning of the recycling material increases the uptime of the smelting furnaces by significantly reducing the amount of unwanted slag.

Components made from steel, nodular cast iron, and grey iron can be processed by mass finishing equipment.

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Forge & Foundry, Part 1 – Shot Blasting Systems

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 finishing effect.

When properly applied prior to finishing, blasting achieves three key aspects of the finishing process:

  1. Cleans and descales surfaces
  2. Creates a uniform texture on the part and blends the surface
  3. Enhances paint adhesion
Continue reading Forge & Foundry, Part 1 – Shot Blasting Systems