Combining the benefits of two proven technologies creates a perfect low Ra surface finish that improves the resistance of scuffing of the mating components, uniformly retaining lubricant while optimizing excellent fatigue strength.
The combined process is especially applicable to high performance gears in the aerospace and motor sport industries as well as other precision engineered components that operate under high stress conditions. While it is well known that shot peening increases resistance to fatigue failure and provides other benefits, tests have shown that the uniform surface that a controlled shot peening process creates is a perfect condition for a subsequent super-polishing process that is conducive to high performance, low operating temperatures, and retention and uniform flow of an even layer of lubricant.
High performance motor sport components such as bearings, gears, camshafts, cam-followers etc. normally require very low Ra surface finishes, but polishing to an absolute “glass” like surface would not be acceptable as some lubricant retention is key to temperature control and prevention of wear, so lubricants are designed to control temperature, minimize wear and friction, as in an F1 engine, uniform distribution of the lubricant is vital, some would say it is the engines lifeblood as it protects critical components and prevents power loss caused by deprivation of contact surfaces, likewise, aerospace engine bearings and gears operate in extreme conditions where the same surface finishing lubrication criteria applies.
Many advances have been made in the development of lubricants to operate and perform in high stress and high temperature conditions. If the mating interface surfaces of the components have a low Ra with extremely fine pockets (dimples) that are uniform and consistent, the correct amount of lubricant will be retained and distributed, performance and life of the engine is increased, and scuffing is greatly reduced.
Typically, the surface of a high performance component before shot peening and super-polishing is inconsistent, as the peaks and the valleys vary in height and depth. Shot peening alone will not produce the required Ra surface, and vibratory finishing alone will not necessarily provide the stress relieving qualities of the shot peening process, and in order to truly uniformly reduce the deep valleys, the vibratory process time can be excessive.
When the parameters of the shot peening process are precisely controlled (shot size, shot type, blast velocity, media flow etc.) a surface condition is created that has uniform peaks and valleys. This means that before the components are treated in the vibratory super-polishing process, the surface finish is reasonably uniform but importantly the valleys are consistent in depth, which means that the micro pockets remaining after the super-polishing process are perfect for lubrication retention and flow distribution.
Both stages of the process will maintain any critical component geometry and dimensions. It is very important to add that both the shot peening and polishing stages must be precisely controlled, as conventional shot blasting and vibratory finishing processes will not produce the required surface and will result in excessive stock removal.
Depending on the material of the components to be finished and the surface finish required, either a paste type process or a chemically accelerated process is applied; both create an “Isotropic” surface. The geometry and the power of the vibratory finishing machine is also a key factor in achieving the desired finish.
The final surface finishing is always our first consideration. Before we proceed, there is a process of evaluation in place on how to best achieve the desired results. There are variety of finishes we can apply. Each process is different, every result can be customized to fit client specifications. From rough to lustre… contact Vibra Finish for your own processing.
Mass finishing processes can be configured as either batch systems, in which batches of workpieces are added, run, and removed before the next batch is run, or as continuous systems, in which the workpieces enter at one end and leave at the other end in the finished state. They may also be sequenced, which involves running the workpieces through multiple different mass finishing processes; usually, the finish becomes progressively finer. Due to the random action of the processes, mass finishing is as much an art as it is a science.
Mass finishing is a group of manufacturing processes that allow large quantities of parts to be simultaneously finished. The goal of this type of finishing is to burnish, deburr, clean, radius, de-flash, descale, remove rust, polish, brighten, surface harden, prepare parts for further finishing, or break off die cast runners. The two main types of mass finishing are tumble finishing, also known as barrel finishing, and vibratory finishing. Both involve the use of a cyclical action to create grinding contact between surfaces. Sometimes the workpieces are finished against each other; however, usually a finishing medium is used. Mass finishing can be performed dry or wet; wet processes have liquid lubricants, cleaners, or abrasives, while dry processes do not. Cycle times can be as short as 10 minutes for nonferrous workpieces or as long as 2 hours for hardened steel.
Deburring machines come in wet and dry varieties. Vibra offers both types of machinery and both methods of finishing processes. Dry machines may be less expensive, but they do require some kind of dust collector, either dry (basically a big vacuum cleaner) or wet (which forces all grinding debris into a wet tank to cool and capture the debris, reducing the risk of fire or explosion).
Dry machines work well for grinding certain parts of similar material, all carbon steel, for instance. But wet deburring machines are an absolute must when grinding different metals, such as aluminum, which can produce combustible dust. If combustible dust is left in a dry dust collection system when steel is run, the sparks created from the steel can ignite the remaining dust, causing a fire or explosion. A wet system, on the other hand, creates no metal dust and so usually does not present such hazards.
Wet machines typically have ancillary equipment, such as a filter and a drying unit. The filter separates the grinding debris from the coolant and recirculates the coolant to spray where the grinding is taking place. The drying unit can include squeegee rolls that push the coolant off of a deburred and grained part, as well as a blower that removes the remaining liquid.
Various abrasive media may be integrated into an automated deburring system. Most have at least one wide-belt abrasive that rotates on a drum, and many have additional barrel brushes that span the width of the work area, as shown in the configuration at the top. Several specialty abrasive heads, including rotating brushes and discs (bottom) also are available. The abrasive choice depends on application requirements.
In most applications, wet deburring machines can prolong the life of abrasive media. With the right coolant, abrasive media can last even longer. Using water-soluble coolants,usually 95 percent water mixed with 5 percent coolant chemical, may almost double abrasive life versus using water alone.
If you have:
Flat parts that stick together
Parts sensitive to water
Thin parts prone to bending
Send your sample parts to our processing lab for a free assessment.
Vibra offers a rust removal service for our customers. This process is similar to rust inhibiting, but derusting process removes only the rust from the part – all other exposed metal along with their tolerances will not be affected. Afterwards, all types of rust inhibitors are applied to the part for rust protection. The total derusting process uses no harsh acids and leaves no powder residues on the parts.
Once again, all shapes and sizes are accommodated, packaged to the customers’ specifications. All services are performed with quick turn around and utilizing environmentally friendly methods. We also provide both pick-up and/or delivery service.
Surface rust is an unwelcome phenomenon during the humid days of summer.
Whether the parts are manufactured locally, or rusted during a sea voyage, they cannot be used in automotive, or any other, assembly. Vibra has a rust removal process, incorporating an industrial wash and rust inhibit protective coating with our proprietary rust inhibitor. A corrosion inhibitor is a chemical compound that, when added to a liquid or gas, decreases the corrosion rate of a material, typically a metal or an alloy. The effectiveness of a corrosion inhibitor depends on fluid composition, quantity of water, and flow regime. A common mechanism for inhibiting corrosion involves formation of a coating, often a passivation layer, which prevents access of the corrosive substance to the metal. Permanent treatments such as chrome plating are not generally considered inhibitors, however. Instead corrosion inhibitors are additives to the fluids that surround the metal or related object.
Parts are returned clean, dry and rust inhibited.
Gauging is a service where the customer supplies us with certified gauges to check the tolerances of the part after any of our finishing processes. Vibra Finish provides a sorting and gauging services. Customers parts are sent for sorting to look for visual imperfections, these can consist of mixed parts in bins, parts that have been mistyped, or poor coatings.
During the gauging and sorting process all bad parts along with the acceptable parts are returned to the customer.
We also apply gauging to our finishing processes to make sure that the actual product meets exactly required specifications and blue print dimensions.
An Almen strip is a thin strip of SAE 1070 steel used to quantify the intensity of a shot peening process. This test is widely used and the requirements for check are specified in standards. The most rigid requirements are applicable for Almen strips and checking devices (Almen gauges) used in the aerospace industry. The generic requirements can be found in SAE specifications.
Developed and patented by John O. Almen, the strip was originally supported by 2 knife edges; later improvements see it being supported on 4 small balls. The strip is placed in the chamber in place of the item to be shot peened, usually near to an area of the item where the result is deemed critical, sometimes located by a special fixture. Compressive stress introduced by the peening operation causes the strip to deform into an arch, which is measured using a gauge.
Almen strips are classified into 3 types: ‘A’, ‘N’, and ‘C’. They differ in their thickness, while they have the same width and length.
Almen strip of “A” type is predominantly used for shot peening with cast shot or cut wire shot.
“N” type strips are used usually for glass bead peen and ceramic bead peen.
“C” type almen strips are used more rarely and are thicker than the other types.
Although similar, the specification for Almen strip dimensions of the same type slightly vary from one company/organization to another. The Almen strips are made from plain carbon steel SAE 1070 and have hardness about 45 HRC.
Shot peening is used on gear parts, cams and camshafts, clutch springs, coil springs, connecting rods, crankshafts, gearwheels, leaf and suspension springs, rock drills, and turbine blades. It is also used in foundries for sand removal, decoring, descaling, and surface finishing of castings such as engine blocks and cylinder heads. Its descaling action can be used in the manufacturing of steel products such as strip, plates, sheets, wire, and bar stock.
Shot peening is a crucial process in spring making. Types of springs include leaf springs, extension springs, and compression springs. The most widely used application are for engine valve springs (compression springs) due to high cyclic fatigue. In an OEM valve spring application, the mechanical design combined with some shot peening ensures longevity; however, automotive makers are shifting to more high performance higher stressed valve spring designs as modern engines evolve. In aftermarket high performance valve spring applications, the need for controlled and multi-step shot peening is a requirement to withstand extreme surface stresses that sometimes exceeds material specifications. The fatigue life of an extreme performance spring (NHRA, IHRA) can be as short as two passes down a 1/4 mile drag racing track before relaxation or failure occurs.
Shot peening may be used for cosmetic effect. The surface roughness resulting from the overlapping dimples causes light to scatter upon reflection. Because peening typically produces larger surface features than sand-blasting, the resulting effect is more pronounced.
Shot peening and abrasive blasting can apply materials on metal surfaces. When the shot or grit particles are blasted through a powder or liquid containing the desired surface coating, the impact plates or coats the workpiece surface. The process has been used to embed ceramic coatings, though the coverage is random rather than coherent. 3M developed a process where a metal surface was blasted with particles with a core of alumina and an outer layer of silica. The result was fusion of the silica to the surface. The process known as peen plating was developed by NASA. Fine powders of metals or non-metals are plated onto metal surfaces using glass bead shot as the blast medium. The process has evolved to applying solid lubricants such as molybdenum disulphide to surfaces. Biocompatible ceramics have been applied this way to biomedical implants. Peen plating subjects the coating material to high heat in the collisions with the shot and also must be available in powder form, limiting the range of materials that can be used. To overcome the problem of heat, a process called temperature moderated-collision mediated coating (TM-CMC) has allowed the use of polymers and antibiotic materials as peened coatings. The coating is presented as an aerosol directed to the surface at the same time as a stream of shot particles. The TM-CMC process is still in the R&D phase of development.
A jet spray washer cleans by flooding the parts with warm chemical solution and high chemical concentration to clean the parts. In the power wash process the parts are blasted with hot chemical solution utilizing the hydraulic impact force of the cleaning solution as the primary cleaning mechanism. A parts washer utilizing the power washer process operates at a very low concentration of cleaning detergent. The lower concentration causes the cleaning solution to last longer before it becomes supersaturated and requires disposal. Additionally, a low concentration of cleaning chemicals allows for easier rinsing of the detergent from the parts thereby minimizing rinse cycle requirements thus saving water and cycle time. A final factor used in the power wash process is an oscillating manifold system that is non-synchronous to the rotation of the turntable. This system assures that the blasted solution reaches all areas of the parts load that are otherwise blinded by the stationary manifolds used in the jet spray process. All things considered the power wash process is superior to the jet spray process for faster more thorough parts cleaning cycles while minimizing detergent use and waste generation. The power wash process is generally effective for difficult soil removal applications such as burnt hydrocarbons, paint, scale, varnish, carbon, mastic, or rubber. Additional power wash types of applications generally include cleaning diesel engines, aerospace components, aluminum automobile engine parts and rolling mill equipment.
There are some considerations when using the “power wash” process in that comparatively high horsepower, thus high-current motors requiring an adequate power source, are utilized with correspondingly high washing pressures that require the parts to be adequately secured to the turntable. The “jet spray” process is found to be adequate for cleaning applications that do not involve removal of difficult soils but in general the power wash process is the superior cleaning process.
A parts washer is a piece of equipment used to remove contaminants or debris, such as dirt, grime, carbon, oil, grease, metal chips, cutting fluids, mold release agents, ink, paint, and corrosion from workpieces.Parts washers are used in new manufacturing and remanufacturing processes; they are designed to clean, degrease and dry bulk loads of small or large parts in preparation for assembly, inspection, surface treatment, packaging and distribution. Parts washers may be as simple as a stand-alone basket immersion washer, or they may be as complex as a five-step deburring, aqueous tumbling, rinsing, drying and paint coating machine. Parts washers are essential in maintenance, repair and remanufacturing operations as well, from cleaning fasteners, nuts, bolts and screws to diesel engine blocks and related parts, rail bearings, wind turbine gears boxes and automotive assemblies.
A parts washer is distinctly different from a pressure washer in that parts washers typically clean parts automatically in an enclosed cabinet, while pressure washers typically have a single spray jet mounted at the end of a manually operated wand. Modern industrial technology makes it possible to combine many parts of the finishing process into one. As an integrated part of the manufacturing process, automatic parts washers are able to load, wash, rinse, dry and unload parts based on a preset computer-controlled program and the help of a conveyor belt to save time, money and man-power and ensure a quality product; innovations are being made to ensure parts washers are water and energy saving.
Traditionally, chemical solvents have been used to strip parts of grease and dirt during the cleaning process, but recent environmental concerns and regulations have encouraged the innovation of natural, non-chemically based solvents. Ultrasonic cleaning is the latest technology in environmentally safe precision surface cleaning.
Parts washers were originally developed for use in automotive transmission and engine repair shops as a way to improve the function of simple soak tanks. Soak tanks are vats filled with a mixture of water and detergent, which take hours to “soften” the built-up road grime, fluids, tars and oils enough to be manually rinsed off prior to disassembly and repair.
Since the late 60’s,many methods of parts cleaning have been developed with improved levels of safety and lessened environmental impact. Stoddard solvent, gasoline, diesel fuel, and kerosene were commonly used to clean and degrease parts. Then, chlorinated solvents in vapour degreasers became an industry standard. During the 1980s environmental and safety issues led to the banning of chlorinated solvents for parts cleaning. Aqueous-based cleaning systems took on new prominence that led to many improvements, in the systems and the processes. In 1971, Gary Minkin developed an aqueous based parts washer for degreasing automobile parts. The Minkin breakthrough used the force of hydraulic impact pressure to significantly improve the cleaning power of the aqueous parts washer.
Wheel blasting is a different method of blasting a surface in order to clean a metal product. Instead of using high pressure air to propel beads, a spinning wheel is used. The centrifugal force of the spinning wheel propels beads at an adjustable rate in order to fine tune the abrasiveness of the clean. A wheel machine is a efficient method of blasting, since the abrasive (typically steel shot, cut wire, pellet, or grit) is recycled throughout the operation.