Industrial assembly is a major part of the production. It directly affects product quality and the life cycle since it is the last step of the manufacturing process.
One of the most commonly used fastening methods in industrial assembly is screw-fastening assembly. Threaded fasteners are the actual nuts and bolts of ensuring dependability on the production floor. They hold things together and keep them in place. While there are complicated fixes for certain joint problems, the most durable joints boil down to getting the basics right. Here are some crucial fastening factors to look out for to ensure a strong fastening system.
The ability of the operator
High-speed production and numerous screws can result in missing screws and compromised quality during fastening regimes. Using batch counting and line control, an operator can ensure quality the first time. Sometimes, an operator may need to label each screw to ensure that they are all securely attached. Screw counting and line control capabilities in the screwdriver emit a signal to the line, and then only, the next set comes.
Quality of thread and engagement.
The length or number of threads engaged between the screw and the female threads is referred to as thread engagement. Bolted joints are engineered to be such that the bolt shank breaks in tension before the threads fail in strain. Nonetheless, this requires basic thread engagement. Due to the majority of the bolt stress being applied to the first few threads, assess the condition of the first few threads being engaged.
To avoid short bolting, make sure the bolt sticks through the nut a couple of threads. Nuts should not be flush with the ends of bolts because the lead threads are not complete. Instead, they should be inserted through a few threads.
Alignment of matched components
Make sure the two matching surfaces are level. This ensures that the bolt load is perpendicular to the joint and results in equal stress on the joint with continuous compression. Furthermore, if the surfaces are not uniform, some joints may be prone to leakage.
The finish of the fastener
When tightening the bolt, a portion of the turning power is used to overcome thread friction and, more crucially, the nut and washer engagement. Even if the applied torque is rigorously regulated, there are other factors at work that impact the amount of friction present. These include a fastener, material, thread class, thread type, thread condition, and many others. Therefore, we can never achieve a uniform clamping force, no matter how best we try.Using torque control methods, lubricating the fastener improves the results even further.
Size and quality of bolts
The optimal clamping pressure for each bolt is influenced by two concepts known as clamp load. In selecting a bolt first, the bolt diameter needs to be considered, another important factor is the bolt class, which is determined by its tensile strength
Tensile strength is dictated by the construction material. Standards bodies have compiled the typical tensile strengths for common bolts into simple standards.
Torque
Torque is critical to the operation of the bolt and is governed by many, often contradictory, parameters. A correctly tightened bolt’s material is somewhat stretched, but not beyond its elastic limit. The bolt material, which is typically steel, resists this natural stretching and exerts a clamping force on the combined substrates. Similarly, the substrate materials resist compression to balance the clamping pressure; this is referred to as joint preload. The preload is shared by a correctly tightened bolt and workpieces. Over-torqued bolts that are stretched past their elastic limit are significantly weakened, reducing their effective load capacity. An under-torqued bolt or screw may create an insignificant gap between the workpieces, which may appear inconsequential at first, but the space between the workpieces will expand during constant dynamic loading or other operational pressures. A fissure in the joint indicates that there is no joint preload. Without the return force of the compressed substrates, the bolt must rely exclusively on itself for joint assembly, which eventually leads to joint failure.
Washers types
Joint relaxation occurs to some extent in all fastened joints. This often occurs because of the surface of embedded parts or soft parts such as such as gaskets, plastics, or spongy material collapsing under the clamping force created by a torque fastening condition. Several ways may be used to lessen the effect of “relaxation of joint,” including:
1. Tighten the fastener, then untighten and retighten the joint.
2. Enhancements to the fastening joint (such as replacing soft gaskets with a sealing compound).
3. Tighten the fastener, wait a few seconds, and then tighten it again (this can be done repeatedly).
4. The final torque is applied using a power assembly toolset to a low RPM.
Proper accessories
A socket is also a type of tool. These products are available in a variety of shapes and sizes, and you must choose the appropriate design and size for your application. During the fastening procedure, sockets are subjected to continual tension. High wear resistance and elasticity are important factors depending on the fastening application.
With the investment made in each power tool, you must ensure that you have the right socket to get the best performance out of the tool while also assuring user safety.
Air Pressure
Airpower tools are usually rated at 90 psi (6.2 bar). They may function under different pressures, with diverse results. Lower pressures result in lower power-to-weight ratios, which negatively impact production. Higher pressures may result in improved performance but at the expense of decreased durability, shortened tool life, and increased service and maintenance costs. Because of the proportional link between torque and supply pressure at the tool inlet, altering air pressure may also affect work component quality. Similarly, if the supply pressure at the gun changes greatly, the paint spray may be excessively sparse or too thick. Close management of the air supply pressure to air tools may enhance quality control and, if done correctly, can reduce the compressed air system’s energy demand.
