This article will give a detailed discussion on metal shims.
After reading, it is anticipated that one should be able to comprehend the following:
What are metal shims?
How are metal shims made?
Types of metals used as shims and their specific benefits
Industrial and domestic applications of metal shims
Advantages of various metal shims
Considerations when choosing metal shims
And much more…
Chapter One: What are Metal Shims?
Shim Definition: The material used to cover empty spaces is referred to as a shim. For instance, window and door jamb construction frequently involve the usage of construction shims. A shim can be made from materials on hand, especially when attempting to level a table being worked on, or it can be made out of metal and utilized to produce huge equipment. Shims are important components that can be used for a variety of purposes. Shims can be utilized by novice designers while putting an assembly together. Shims, however, are crucial to a mechanical device's ability to correctly function when it needs to be corrected.
Shims are frequently employed as compensators to close tiny gaps between components inside a device. They are little, delicate objects that are frequently constructed of metal. A device's internal parts can easily become damaged if there is a loose fitting component because they may collide. These parts might be essential to the machinery's operation. If these parts are damaged, the machine's functionality may be readily jeopardized. Shims can therefore save on manufacturing time and expenses by being able to fit into the gaps. Moreover, increase a piece of equipment's longevity.
Chapter Two: How are Metal Shims Made?
Shims are made using many methods. We examine some of the more common methods below.
Stamping/Pressing
Making the tools following shim specifications is the initial stage. Die-cast steel rules function like cookie cutters. A sharp pre-shaped steel rule die is first applied to a shim material to cut pieces.
For each new purchase of shims, steel rule dies are produced to order. To lower the one-time tooling expense so that repeat customers can order the same shims without paying a fee, the tooling is constructed using economically sound materials. The material is selected and cut on the stamp press machine after the die has been made. Cutting shims on the stamp press needs precision because the machinist must reduce material waste. The shims are then finalized by being deburred. Before packing the orders for transportation, they are checked for edge quality and correctness.
The manufacturing method for stamp press shims consists of the following four steps:
First, pickers choose the proper shim material and place tooling orders.
Next, the cutter uses a stamp press to cut the material, increasing material utilization and cutting costs.
Then, to ensure quality, the cleaner carefully examines the shims.
Finally, the shims and shim stock are packaged by the packer to prevent damage during delivery.
Metal shims tend not to be cut with a stamp press and eventually wear down the die.
CNC Laser Cutting
The CNC laser cutter uses a similar procedure to the stamp press for the most part. However, instead of ordering a unique steel rule die, the laser cutting machine is programmed to use the associated laser to cut the shims. Metals and other shim material are typically cut using a laser cutter. There are still four steps in the shim production process, but now the employee programs the machine to the required size rather than selecting the material and tooling.
Water Jet Cutting
An abrasive separation technique for shaping metal shims is water jet cutting. An abrasive (grinding powder) is introduced to the water jet during metal cutting. When under high pressure, the water jet precisely slices the workpiece without emitting heat or causing light to reflect, as is the case with laser cutting. This procedure is thus appropriate for materials that are sensitive to temperature.
EDM Wire Cutting
Wire-cut EDM is an incredibly accurate electrothermic separation method for conductive materials when applied to metal. In contrast to other cutting techniques (such as drilling, milling, and turning), it creates an electrical charge between the cutting wire and the workpiece, which is the metal shim, instead of mechanically removing material.
Turning
Like milling and drilling, turning is a machining method that belongs to the group of cutting methods. The shim must be fastened into the turning machine, which rotates around its axis while being stripped of material until the desired shape is obtained. Round pieces are primarily formed through turning. Since turning produces the part's general shape, it is frequently done at the start of a process chain.
Punching and Nibbling
Punching is a manufacturing process that uses a punch press. A tool that matches the shape of the workpiece to be produced is necessary for punching. The tool is made up of two parts. The punch is internally shaped and properly fits through the die. The idea is the same as how a hole punch works. Punch nibbling or nibbling is an alternative to standard punching, which always produces the same form. This incremental process uses several punches to create complex geometry or big punch holes.
Chapter Three: Types of Metals Used as Shims and Their Specific Benefits
Metal shims are classified according to the materials used for making them. Stainless steel, aluminum, brass, copper and carbon steel are among the most commonly used metals.
Stainless Steel Shims
Stainless steel shims feature exact thickness and extremely smooth surfaces. They are ideal for axially spacing objects along a shaft. They are frequently employed to create the extra space required between a bearing and a nearby rotating component. Stainless steel shims are best when used on corrosive areas.
A steel alloy with a minimum bulk content of 10.5% or 11% chromium is known as stainless steel. Industrial shims and washers are frequently made of stainless steel because they do not rust, corrode, or discolor as easily as regular steel. When the alloy type and grade are not specified, it is sometimes known as corrosion-resistant steel, or CRES. The level of chromium in stainless steel sets it apart from carbon steel. A passive layer of chromium oxide occurs on the surface of stainless steel when there is enough chromium present to prevent additional surface corrosion and the spread of corrosion into the metal's internal structure. The number of stainless steel grades exceeds 150.
Austenitic stainless steels are generally recognized for their exceptional stain- and atmospheric corrosion-resistance in both oxygenating and non-oxygenating situations. The magnetic permeability of austenitic stainless steel can increase during cold forming but is non-magnetic in the annealed state. Within the various grades of 300 series stainless steel, for example, different alloying elements impact the material's overall corrosion resistance, appropriate operating temperature range, the propensity to increase magnetism, formability, and welding characteristics. Though all 300 grade stainless steel has these properties, the 306 grade is preferable. Shims are best made of 316 stainless steel in applications involving chemicals, petrochemicals, food, and marine use. The austenitic grade 316 stainless steel offers exceptional strength and outstanding ductility, toughness, and corrosion resistance. Adding molybdenum improves the overall corrosion resistance of grade 316 stainless steel. Additionally, 316 stainless steel is excellent for metal shims, metal packers, and some spring applications.
Aluminum Shims
Aluminum shims are little plates with a horseshoe form used to level off uneven surfaces. Due to the passivation process and the metal's low density, aluminum is noteworthy for its ability to resist corrosion. However, despite having excellent corrosion resistance in most situations, different alloys of aluminum have varying degrees of corrosion resistance and strength.
Applications of Aluminum Shims
There are a variety of uses for aluminum shim stock, including but not limited to the following:
Newly assembled machinery
Setup of tools and dies
Work on prototypes and small runs
Shims made of aluminum are lightweight. Aluminum and its alloys are used to make structural components, which are crucial to the aircraft industry as well as other sectors of the building and transportation industries. Standard shim thickness for quick turnaround of shims, spacers, and washers is 0.05mm to 3mm (.002" to.125").
Aluminum Wedge Shims
Aluminum shims are prevented from separating when stacked by ridges. As a result, they support heavier weights than plastic tapered shims, making them better for aligning shafts and axles. The answer is to screw through the center mounting hole for further stability. Normally called pinion shims, wedge shims and tapered wedge shims are simple to use for leveling and aligning dead loads.
Laminated Aluminum Shims
Utilizing laminated shims offers advantages, including cost savings by obtaining different close tolerances more quickly and reducing assembly time. The type of application must be considered while selecting a laminate material. For example, when the application is subjected to temperatures less than 300°F and no pressure, aluminum should be used as the laminate material.
Why Use Aluminum Shimming?
Due to its extremely low density, aluminum is frequently used when weight is an important consideration. Furthermore, its low reactivity is also greatly desired. This makes it a typical material used in the food and beverage industry. Not to mention, it has outstanding corrosion resistance.
Low Manufacturing Costs
Aluminum is a widely used material because of its availability, relatively inexpensive cost of production, and ability to be recycled. Theoretically, aluminum is completely recyclable and maintains all of its original properties in the process. For example, 42% of cans and 95% of the aluminum used in vehicles are recycled in Europe.
Environmental Benefits
As previously indicated, there is no shortage of aluminum. Thus, that isn't the primary justification for recycling this material. In actuality, this is because scrap aluminum can be melted with less than 5% of the energy needed to generate aluminum from ore. Reusing the discarded material is, therefore, much more affordable and environmentally friendly.
To Enhance an Alloy’s Mechanical Properties
Aluminum is frequently used as a component of alloys to enhance the material's mechanical properties. Copper, zinc, magnesium, manganese, and silicon are some more alloying elements. Its typical applications are identical to those of household foil and beverage cans. For example, aluminum foil is typically made from an iron and silicon alloy to enhance its properties.
Weight and Malleability Concerns
Aluminum is the best material for shims and foil when weight is a concern, and the material's comparatively inexpensive cost is crucial. In addition, aluminum is a crucial metal in many industrial applications where precision is required since it is very light and malleable.
Brass/Copper Shims
A brass shim is extremely adaptable and frequently employed when a certain amount of stiffness is still needed. Additionally, the material's characteristics make it helpful in applications where corrosion issues may arise. A brass shim can be easily stamped, bored, cut, machined, sheared, and drilled to fit most applications. Cold rolling is used to form a half-hard temper on a brass shim.
Benefits of Brass Shims
Brass shims are a flexible material mostly used in the plumbing, automotive, heavy industrial, and construction industries. Additionally, they have uses in model train and airplane activities. It is frequently utilized in the following areas:
Bearing spacing
Washers
Dies
Device repair
Maintenance of machines
Parts and components manufactured to order
Since brass is an alloy of copper that has a variety of special qualities that make it particularly suitable for shims, some of its properties are explained below:
High Malleability
Shims are a typical tool for numerous industries, especially those involving machinery. They are frequently used to close gaps, level out surfaces, produce more precise alignment, and compensate for wear to help lessen the need to replace more expensive parts frequently.
Shims will typically need to be produced to a specified size and thickness to act as a space filler or improve alignment. Because it is a softer metal with a lower melting point, brass works well in this application. Compared to bronze and zinc, it is more pliable and is simple to cast.
Low Friction
Brass has a low coefficient of friction because it is a softer metal. Because of this, it is a suitable option for places where it is crucial that sparking does not happen, such as around explosive gasses. Additionally, it is a superb heat and electrical conductor. Despite being a soft metal, it is more durable and robust than copper. However, the amount of copper and zinc in the brass will determine how strong the metal is.
Resistance to Corrosion
Brass is frequently used in aquatic conditions for pipe and tubing. This usage is a result of its strong corrosion resistance. Brass also exhibits resistance to corrosion in conditions that contain alcohol, fuel, oil, kerosene, or gasoline in addition to water. Additionally, the tarnishing resistance of this metal is very high.
Excellent Recyclability
The amount of recycled brass in existence is about 90%. The absence of ferromagnetism in brass is one of the properties that make it a highly recyclable metal. Brass can typically be separated from other metals by removing the magnetic metals with magnets due to its lack of magnetism.
Microbiological Qualities
Brass possesses antibacterial qualities, just like many copper alloys. Brass helps eliminate some bacteria and diseases because of the copper it contains. This quality makes brass a viable option for shims utilized in situations like the food industry or hospitals where sanitation may be particularly crucial. The kind of bacteria present and the media they are in will also determine how rapidly they are eliminated.
Carbon Steel Shims
Carbon steel shims are galvanized to reduce rusting and corrosion that could develop over time. With a horseshoe feature, structures that may already be fastened to a surface can be leveled and packed.
Applications examples include:
Work with structural steel
Installation of mezzanine flooring and steel shelving with thicknesses ranging from 1 to 10 millimeters
Chapter Four: Industrial Applications of Metal Shims
Uses in Oil and Gas Industry
Precision metal shims are used in various oil and gas industry applications. Metal shims are frequently utilized in various parts, including pumps, compressors, turbines, motors, gearboxes, and torque converters. Throughout the entirety of the equipment's life cycle, from assembly to installation to refurbishment and retrofitting, they can result in cost and labor savings. Below are some of the uses of metal shims in the oil industry:
Space Compensators: Increasing tolerances can result in axial motion in shafted assemblies (such as motors, generators, pumps, gearboxes, and torque converters), which can significantly shorten the lifespan of the assembly. These tolerances can be absorbed using precision metal shims.
Thrust Washers: When applied stresses are not too great, metal shims can function as thrust washers, an affordable substitute for roller thrust bearings.
Shims for Mating Surfaces: Precision metal shims can be fitted in the space between two components’ or assemblies' mating surfaces. They have many benefits above just mating the assemblies: By using a precision shim to make up for the space created, mating surfaces on castings or machined components can be produced with less exact tolerances, resulting in lower production costs. In addition, metal shims can serve as sacrificial plates by absorbing the wear that would typically be caused by natural friction, wear, and tear, on the mating surfaces when constructed of a somewhat softer material than the mating assembly. Because there is no longer a need to resurface the mating components, this technology also significantly decreases turnaround time and costs during equipment replacement or retrofit operations.
Leveling Shims: To ensure precise alignment of two assemblies, leveling metal shims, also known as pump shims or foot shims, are inserted at the base of a mating component. This is crucial to avoid any angular misalignment between spinning components, which could lead to premature failure.
Other Industrial Uses for Metal Shims
Shims made of stainless steel are used in corrosive or humid situations to prevent corrosion and the need for replacement.
In addition, metal shims are used to align equipment after adjustments.
In engineering and manufacturing, metal shims are frequently repositioned for better fit or support of heavy equipment. Furthermore, shims can be used as spacers to close gaps between worn-out parts or to alter clearances, tolerances, and alignments.
Chapter Five: Domestic Applications of Metal Shims
Even with the finest measurements and attention, it's doubtful that a door or window will be completely square without adjustments once installed. Shims are used to make the final adjustments rather than painstakingly cutting a new frame or attempting to nail in an incredibly precise opening. Shims should be used to fill in gaps between the window or door casing and the framed opening after the door or window has been installed.
The first step to gradually level and plumb an element is to wedge a shim between the frame and the neighboring stud. This is done using a level to check that the window or door is moving toward plumb or level as desired. Next, use a hammer or mallet to gently tap the shim into place. It is crucial to follow this procedure. If the first shim is insufficient for the necessary adjustment, then one must place a second shim right next to the first one, but with its face in the opposite direction. Avoiding driving the shim(s) in too deeply because they are challenging to remove once in place. Once the door or window is level and plumb, it will be fastened by driving a nail or screw through the casing, the shim(s), and framing. The final step is to use a tool knife to score the extra shim length and break it off when the window or door is firmly in place and fastened with nails.
Metal shims can be used for more than just windows and doors; they can also level a wobbly toilet, square up cabinets, adjust subflooring and floorboards, and stop outdoor decking from creaking. In addition, metal shims perform the following “domestic” uses.
A motorbike or car engine has valves that open and close repeatedly, hundreds of times per second. A valve's parts deteriorate with time. As a result, the space between the cam lobes and the end of the valve stem gradually gets smaller. The space that has to be filled will be measured by a mechanic using a feeler gauge. The mechanic will use this clearance as a guide when inserting the shims because the manufacturer assembles the valves at this clearance for the best wear. Shims are occasionally used in other automobile components to reduce clearances.
Metal shims can be used to realign the wheels of a car if they become misaligned owing to rust, dirt, or paint that got onto the vehicle in the wrong place.
Shims are included with cycling shoes that contain a mechanism to accept the cleats on a bike pedal so that the cleat height can be changed as needed. These bicycle shoes include a light set and heavy pair of shims.
Metal shims are used in the home craft sector to shield surfaces when using a die-cutting or embossing tool. In this instance, the foundation components are safeguarded against harm as cutting and embossing pressure is applied.
Chapter Six: Advantages of Various Metal Shims
Copper Shims
Affordability
Copper shims lower maintenance costs. Replacing them is much less expensive than fixing or replacing an entire machine when damaged. They also do away with the need for additional labor to repair such machines, thus saving money overall on a business's budget.
Electricity and Heat Conduction
Second, a copper shim is renowned for being extremely compatible with heated and electrical applications. Copper is a basic chemical element that can withstand extremely high thermal and electrical voltages. They are, therefore, frequently employed for cabling purposes. It makes an excellent leveling, spacing, and sealing material because it is a soft, malleable metal that lends itself to customization.
Corrosion Prevention
Finally, due to this material's superb resistance to corrosion, copper shims are regularly requested. Industries that deal with water transfer and piping applications heavily rely on this kind of shim because copper is non-reactive to water. Corrosion is minimal because copper can remain strong and aesthetically pleasing under most circumstances.
Brass Shims
Since brass metal shims have similar advantages to copper shims, brass shims differ from copper because of the following:
Minimal Friction
Because it is considered a softer metal, brass has a comparatively low friction rate. This low friction rate means that a brass shim is a viable option for settings where sparking is required, such as those involving applications that will use explosive gas. In addition, brass is a superb conductor of heat and electricity and, while being soft, is stronger than copper.
Stainless Steel Shims
Stainless steels, on the other hand, are among the strongest shim materials. They have high levels of durability, corrosion resistance, and strength. Stainless steel of the highest quality prevents corrosion when exposed to acids and alkanes. Therefore, stainless steel shims are the best choice for usage in the pharmaceutical and petrochemical industries, and in any other application that calls for a shim that can tolerate high temperatures and durability.
Aluminum Shims
Aluminum may be the best shim material when seeking something lightweight. Shims made of aluminum can also endure high temperatures. The fact that these shims are comparatively non-oxidizing is another desirable quality. Because of this, the shelf life of an aluminum shim is quite extensive.
Robust Shims
Some applications call for a heavier-duty shim that can resist various hostile conditions. Large industrial machinery that operates with corrosives, biologicals, and volatile compounds is particularly susceptible to degradation. Brass shims are frequently used for these applications, especially in saline environments.
Pre-Cut Shims
A variety of sizes and thicknesses (depending on the size of the machine feet) are available to make machine alignment easier.
They feature an insertion tab to make alignment placement and removal easier.
Permanent markings indicating thickness and dimensions make it simple and quick to identify.
Accurate, to increase the duration between machine shutdowns and assure machine dependability
totally flat, ensuring stability and constant machine support across the whole shim's surface.
Burr-free and rounded on the corners to prevent operational harm during alignment positioning
Chapter Seven: Considerations When Choosing Metal Shims
Each shim material will have a unique collection of strengths and weaknesses since every material has unique qualities. Therefore, it is crucial to consider the shim's qualities when selecting the appropriate shim. This consideration will guarantee that the shim will be suitable for the situation and application for which it is intended. For instance, using plastic shims in high-temperature applications would not be appropriate. However, materials made of stainless steel would be effective in that application. In addition other shims are perfect for marine conditions since they won't deteriorate from exposure to salt water.
Material Property
When choosing the right shim, consideration should be given to the material’s composition and its mechanical and physical parameters. Shims are made of a variety of materials and thicknesses. Plastic, aluminum, brass, stainless steel, and cold-rolled, low-carbon steel are examples of materials. These are the most widely used shim materials and meet most design requirements for most applications. However, specialty applications can call for additional materials.
Operating Conditions
An excellent design effectively uses the shim material. In a high-temperature engine application, for instance, a plastic shim is typically improper; instead, stainless steel or cold-rolled materials are preferable. Shims made of ferrous metals, such as cold-rolled or stainless steel, are also not frequently utilized in marine settings. Brass can be used in this situation without suffering from salty deterioration.
Usage
The intended usage of a shim is another aspect. For instance, shims often occupy mechanical space or slack in a setting with static loads. Simply put, some metals prevent static load and static discharge better than others. Additionally, problems like friction and drag wear must be considered. In most situations, these two factors serve as the primary selection criteria.
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