Since it was introduced in the spring of 2023, the STRwrench Compact from Atlas Copco has attracted more and more interest from assembly tool users in manufacturing industries. This innovative torque wrench for use in production combines the functions of a tightening, measuring and testing tool and therefore represents a flexible alternative to conventional tightening tools. Our example shows how the STRwrench Compact can also massively reduce maintenance expenses.
A well-known manufacturer had used dozens of electronic torque wrenches in production, with a large number of product variants, for many years. On many production lines, these manual tools are preferred to power tools for certain production applications. In contrast to continuously working pneumatic, electric or cordless tightening tools, these manual tools do not require any torque arms for torque values above about 50 Newton-meters (Nm). This makes them more agile and allows better access to the joints. Using these electronic torque wrenches, this manufacturer could not only tighten the joints but also measure and test key values such as tightening torque, tightening angle and breakaway or prevailing torque. This gave the manufacturer full control over the tightening results.
No more overloaded tools
However, as the manufacturer used these electronic torque wrenches for longer periods, malfunctions became more and more frequent. The reason for these repeated malfunctions was the arduous working environment typical of industrial plants. Everyone is familiar with the situation: in everyday production, some joints which need to be tightened are relatively inaccessible and there are many obstacles, resulting in impact on the tools. Sometimes, tools are also dropped. These mechanical loads caused by rough conditions make considerable demands on a tool. After a torque wrench had been repaired, it was therefore only a matter of time before it would need to be repaired again. This unscheduled repair work boosted maintenance expenses considerably. This is why the manufacturer was looking for a more economical alternative and took up Atlas Copco’s offer to try out the STRwrench Compact without any obligations.
Error sources eliminated
When the tool was demonstrated on one of the production lines, the first thing that was noticed was its sturdy design. “This wrench really feels solid. It lies easily in the hand without any effort,” was the first impression of one worker. The tool was then put through its paces.
Another advantage that was immediately apparent was the safe integration of the battery in the handle of the newly developed STRwrench Compact. This provides optimum protection against damage for the battery. Another convincing feature was the large, sturdy color display with an extremely robust housing providing very good protection against knocks and impact. The users found that this was especially important because damage to displays and faults in practically unprotected batteries on the torque wrenches previously used had been one of the main causes of maintenance expenses.
The large color display of the STRwrench Compact features high impact resistance and can be rotated in 90° steps. This means that it is easy to read from any position, even when working overhead.
Another advantage for operators is immediate feedback on tightening results. The STRwrench Compact not only gives an optical indication of tightening progress via LEDs; the color display also changes color to indicate the status of the joint (green = OK, red = not OK). In addition, the unit is equipped with a vibrating handle and a buzzer. These clear optical, haptic and acoustic signals ensure that workers detect any errors immediately and can tighten each joint correctly.
During the comprehensive trials, the customer was not able to try out the full torque range of the STRwrench Compact – from 4 to 400 Newton-meters (Nm). However, the prospect of having a significantly more durable tool with higher accuracy of 1% from 5% of the wrench capacity upwards convinced this customer that it should buy the first tool of this type.
Maintenance expenses saved
Of course, the first production wrench was not the only tool to be purchased by the company. As a result of the positive practical experience gained with the tool, intuitive operation and greater durability, the customer started to scrap the electronic torque wrenches previously used. In the meantime, about 20 of the old tools have been replaced by STRwrench Compact wrenches allowing full traceability and documentation of tightening data.
“During the first six months, we were already able to reduce our repair costs by 40 percent," said the maintenance manager, who was pleased to report the significant savings achieved.
In future, he expects costs to fall still further. The remaining wrenches are gradually to be replaced by smart STRwrench Compact tools when it is no longer viable to repair them after a malfunction.
Calibration work minimized
In the case of earlier tools, the entire torque range of a torque wrench needed to be re-calibrated at regular intervals (measurement chain calibration). Thanks to the modular design and consistent digitalization of the STRwrench Compact, this tool consistently saves a considerable part of calibration expenses.
The unit is divided into two main components, the handle, the body of the unit [1], and the head [2] which provides a mount for tightening attachments and is referred to as a “smartHEAD”. The two elements form two separate units which are simply plugged into each other. Only the smartHEAD needs to be calibrated. This is in line with the Industriy4.0 approach and the idea of lean production as the handling and logistics expenses of the customer are considerably reduced.
The smart production wrench has a further positive impact on the customer’s production budget. If it was necessary to tighten joints with widely divergent torque ranges, customers previously had to invest in two different wrenches. This is not necessary anymore. With the STRwrench Compact, you only need a single handle – with a second smartHEAD.
The STRwrench Compact is another step in the direction of the smart factory, efficiency and zero-error assembly.
[1] The handle of the STRwrench Compact is referred to as the “controller“, as not only the display and the battery but also the on-board controller is integrated in the handle. This is the first time that a high-performance controller has been integrated in a tool of this type: https://www.atlascopco.com/nl-be/itba/products/assembly-solutions/quality-assurance-in-tightening-and-fastening/wrenches/strwrench-controller-compact-sku8059092400
[2] Precise sensors are integrated in the smartHEADS. They measure values such as torque and rotation angle and transmit them digitally to the controller installed on the handle. The head is referred to as a “smartHEAD” because of these smart features: https://www.atlascopco.com/nl-be/itba/products/search-result?search=STR%20Smarthead&isSuggestion=false
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