The threads of a metric flat head screw spiral downward as an assembly operator fastens a medical instrument together. Is the proper torque control being used to keep that life saving medical device together? Tightening down a bolt or screw until it “feels tight enough” is not adequate torque control. That mentality is the path toward costly fastening failures. Ensuring accuracy and precision for any fastening application is critical for all manufactures. Improving safety and performance are key objectives.
What is Torque?
Torque is a “turning” or “twisting” force and differs from tension, which is created by a straight pull. However, we use torque to create a tension.
As the nut and bolt are tightened, the two parts are clamped together. The thread angle in the bolt converts the force applied into tension (or stretch) in the bolt shank. The amount of the tension created in the bolt is critical.
The Importance of Torque Control
The reliability of machine parts subjected to fluctuating loads and stress depends on the fatigue strength of the materials. A threaded fastener, however, relies upon an elastic interaction between the mating components. Its objective is to clamp parts together with a tension greater than any external force trying to separate them. The bolt then remains under almost constant stress and is immune to fatigue. If the initial bolt tension is too low, the fluctuating load in the shank in much greater and it will quickly fail. Reliability, therefore, depends on correct initial tension and is ensured by specifying and controlling the tightening torque.
For low volume assembly applications, often hand type torque tools like a torque screwdriver or torque wrench are adequate to meet the fastening requirements. When the production volume is higher, like an operator fastening hundreds and hundreds of metric SEMS screws a day, an assembly power tool is better suited for the assembly process.
The ergonomic torque arms by Mountz eliminate torque reaction from both power and pneumatic assembly tools. With the EZ-Glider linear and articulated torque arms, a “downward assistant kit” can be installed on the arm to speed up and improve the production process. The system requires no effort from the operator to press downward on the power tool. An assembly operator simply guides the power tool and the cylinder automatically glides the torque tool downward. These kits are ideal for self-tapping applications, as well as other fastening applications.
Day after day, an assembly operator performs hundreds and hundreds of repetitive fastening rundowns. Over time, the repetitive assembly process will expose your operators to potential injuries. The goal for manufacturers must be to protect the operator from any potential injury and make them feel comfortable and secure in operating an assembly tool. An ergonomic mindset helps ensure safer conditions. Torque reaction arms are an ergonomic solution designed to reduce RMI (repetitive motion injury) and CTS (carpal tunnel syndrome).
The EZ-Glider torque arms are designed to improve production and safety during the assembly process. Securely keeping an electric or pneumatic driver in alignment with the fastener, the torque arm prevents cross threading occurring during the assembly process. These tool support systems help remove the operators’ influence during the fastening process and strengthens quality control.
Accessibility to an electric outlet or an air compressor may not always be practical for all fastening applications. Whether an assembly operator is tightening metric fasteners on an automotive assembly line or a field service engineer is fastening some metric bolts in a maintenance application on a solar farm, a cordless screwdriver may be the tool of choice.
Cordless drivers are typically compact and flexible for tight space applications. Battery screwdrivers are portable and convenient to use with many torque applications. When selecting a cordless torque screwdriver, there are important details to review. It’s crucial that you decide what key attributes you are seeking before searching for a battery driver.
At the top of the list should be a tool that enhances quality through precision torque control. You want a shut-off cordless screwdriver the delivers maximum performance. A dependable cordless torque screwdriver that automatically stops when the preset torque is achieved. Selecting a quality cordless driver ensures accuracy, repeatable tool performance, and adherence to international standards.
Finding the proper hand torque screwdriver for your torque application may seem like a daunting and confusing process at times. There are many, many options to choose from when selecting a torque screwdriver. Which tool truly fits my fastening application? That’s the key question you are looking to answer.
When you are unsure of the various differences between screwdrivers, selecting the low cost tool option is the easiest choice. It’s an easy justification. If the torque tool is not adequate or fails, the excuse of …”oh well, the tool didn’t require much investment”… is our acceptable rationalization.
Taking the time to educate yourself and understanding the various torque screwdriver options available is worth the investment. How critical is torque for your fastening application? A lack of torque control with a communications satellite or a cell tower can be a costly mistake. Obviously with an automobile, aircraft or missile, the failure to properly tighten a fastener or bolt to the correct torque specification can have potential catastrophic results. Therefore, is a quality torque screwdriver worth your investment?
Conventional assembly methods cause assemblers to inefficiently fumble with screws that are stored in bins or shaker trays. Fumbling isn’t just a football occurrence. Daily, assembly operators using power tools fumble around picking up screws from bins and slowly align the fasteners onto a bit. In an attempt to grab one fastener at a time, several screws often stick to the operator’s fingers. Screws can easily be dropped across a workstation or fumbled to the ground. Smaller the fastener is, the more extensive the challenge becomes for an operator to efficiently pick-up a screws from a bin and perform the fastening process in a timely, productive manner.
The constant repetition of picking-up and fumbling around with hundreds and hundreds of screws on a daily basis impacts productivity and costs. It’s an unnecessary expense and an inefficient process. And, a potential health hazard if fasteners are dropped and left on the floor, allowing an opportunity for an individual to slip and fall.
Using a screw presenter during the fastening process is a productive option to consider. A tabletop screw presenter is typically small and compact. It is used to organize and automate work areas and production cells. Screw presenters make assemblers and the assembly process more efficient by mechanically presenting a screw to a fixed pick up point. These feeders can be used in combination with most any assembly application and power tool. Alternative methods of presenting a screw are cumbersome and very expensive.