Stainless steel is one of the most widely used metals. Its strength, durability and corrosion resistance make it the perfect choice for a broad variety of industries – from transportation, food and beverage and pharmaceutical to petrochemical, metal fabrication and more.
Most stainless steel can be cut, welded, formed, machined, fabricated and finished. However, the finishing is a tedious process that requires a balance of time and precision. Finishing solutions are designed to help shops increase productivity and create products made to withstand industrial wear and tear. More and more industries are recognizing the importance of workers being able to do their jobs more efficiently, comfortably and with less fatigue. Working better and smarter, however, requires the right tools and processes to consistently achieve the desired finish, especially when working with stainless steel. The tools and abrasives used for the job, grit type, grain and operator technique all affect surface finish.
Achieve the desired finish, increase productivity and maximize cost savings by following three simple steps: Weld better, blend welds faster and finish smarter.
Step 1. Weld better
A welding helmet is an investment, not a necessity. But with so many options available, it can be hard to know which helmet makes the most sense. The better helmets are not only comfortable for all-day use, but also have auto-darkening technology and feature the settings required to do the job safely and efficiently.
Auto-darkening helmets are an effective way to ensure protection of a welder’s eyes and face. One advantage of this technology is that the welder does not have to flip up their helmet to perform other tasks or to get a sense of the work area. This can prevent neck strains and injuries by not having to remove, flip or change helmets.
When looking into auto-darkening technology, there are many factors to consider. For example, the welding lenses are offered in fixed or variable shades. Variable shade allows the welder to perform a wider variety of welding applications, while single shade, though cost-effective, only offers one dark shade. Welders should select a lens based on personal preference, while considering the variety of welding tasks they will be performing. Including features like grind mode on a welding helmet adds the capability to grind down a weld or cut a piece of metal without having to change face protection and carry additional PPE equipment when in the field. This saves both time and money.
HD technology specific to Walter’s ArcOne helmet increases the range of visible light when looking through the lens and while welding. By increasing the range of light, more natural colors can be seen, providing a clearer, more defined view of the work area. This is especially important when working with stainless steel.
Step 2. Blend welds faster
Finishing takes significant time and labor, which is why reducing the number of steps in the finishing process is crucial. With the right combination of tools, manufacturers can achieve significant time and cost savings.
Using the wrong abrasive can lead to a poor removal rate as well as discs being discarded before they have been fully used. An unproductive and long process can result in operator fatigue. Both factors can lead to high costs and inefficient production.
It is, therefore, best practice to choose the abrasive carefully. An abrasive that is too coarse can gouge the surface, making a smooth blend impossible and ruining the workpiece. Novice operators should start with a finer grit. Once familiarized with the speed, pressure and angle, they can move up to a coarser abrasive for faster material removal.
Clean the workpiece before starting any finishing job to remove contaminants on the surface. It saves the shop from having to fix any scratches down the line.
When choosing a flap disc, look for a product family that offers a complete solution, regardless of the weld, removal rate or material.
Flap discs that are made with cold curing glue and air dried, such as the Enduro-Flex finishing disc, tend to have a longer service life. Keep an eye out for additional features such as:
- Trimmability. Flap disc backings made from less dense wood fiber composite are easier and safer to trim compared to backings made from nylon or fiberglass. It also extends the life of the disc. When the flaps wear down to the outer diameter of the backing, trim away 1/4 in. of the backing at a time to expose fresh abrasive grain, extending disc life and providing a new cutting edge.
- Balanced flap discs. Make sure the disc meets or exceeds the ANSI standard. This will guarantee vibration-free weld blending.
- Threaded spin-on application. Quickly mount or remove a flap disc without needing a mounting flange nut or pin key. Discs are available with an ultra-resistant built-in threaded arbor or a metal hub for quick and easy disc changes without compromising operator safety.
To maximize performance and productivity, it’s important to keep in mind the application and the material that will be worked on, as this will impact the selection of abrasives.
For example, when working on steel structural parts that require a coating, a coarser grit flap disc like 36/60 grit will help get the job done faster while providing a paint-ready finish that can be coated right away. On the other hand, when working with stainless steel to achieve a sanitary #4 brushed finish for the food and beverage industry, different steps need to be followed to achieve a sanitary finish. Start by using a disc that provides a finer finish, but still offers high performance, like the Enduro-Flex two-in-one product, followed by finishing drums.
Certain flap discs self-sharpen as they work, providing both an aggressive removal rate and an excellent finish. The operator may already know what finish to expect from different grits, but certain abrasives like the Enduro-Flex Turbo have a dual grit. Its unique 36/60 grit ceramic grain blend removes material quickly like a 36 grit, but leaves a finer 60-grit, paint-ready finish, saving a valuable step in the finishing process.
As a general rule, apply more pressure when removing material versus polishing. Applying the right pressure and angle keeps the material from overheating and prevents discoloration. For the best performance, always use a Type 27 flap disc at a working angle of four to 10 degrees. Never use it at a flat working angle.
It is always better to apply moderate pressure. Let the tips of the flaps do the work. Too much pressure can cause overheating and discoloration of sensitive metals. Also, heat can cause loading or glazing of the abrasive flaps. Specialized flap discs are designed to enable a better airflow to cool off the surface and use unique coatings to extend the disc life.
Step 3. Finish smarter
Whether working with stainless steel, aluminum, brass, copper or other alloys, selecting the right power tool is key for finishing applications.
Match any linear finish and reduce finishing costs by using a versatile variable-speed tool like the Line-Mate III drum sanding tool. Be sure to use the right speed. Finishing drums are used at much lower speeds than flap discs – generally at 2,000 RPM.
Also, working with a dedicated tool ensures that the RPM remains constant under load for a uniform finish every time. Ergonomically, the right power tool allows the operator to maintain a better posture and uniform pressure to achieve the desired finish quickly and with minimal effort. Keeping consistent pressure and steady movement will help produce a straight and uniform linear finish.
Pair the tool with individually balanced drums to avoid vibration and to provide a consistent and uniform finish. Higher quality drums have noticeably less vibration as they are individually balanced during production using laser technologies. The specially placed weights compensate for variations of density of the non-woven material.
Prioritize high-quality, non-woven grain and fiber to provide high performance throughout the life of the product. Higher quality materials decrease the risk of smears and contamination of the surface. Reduce changeover time with the threaded spin-on drums, which also eliminates the need for a clamping nut or extension tools.
To quickly achieve a brushed linear finish, use drums like Walter’s two-in-one to combine two finishing steps into one. The coated abrasive cloth of the drums cuts aggressively while interwoven flaps produce a satin linear finish. Other standard drums are offered in various grit levels to reach a wider range of finishes in a multi-step approach. Blendex drums are used to polish, burnish, blend, deburr, clean and brighten, depending on the grit level.
Walter Surface Technologies Inc.
