ACE Issue 29 2021 | Page 18

Accuracy and rigidity of actuators are crucial for metal machining

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When assembling prefabricated metal components and frames , exacting accuracy is consistently needed to ensure a productive work rate and to avoid rejects . To achieve this , drills , routers and cutters have to provide a controlled action that ensures precision and avoids deflection during high speed operation . This relies on the rigidity and precision provided by the actuators , and a multi-axis linear system can help OEMs design more productive , high performance machines . Gerard Bush of INMOCO explains the key considerations in actuator selection for metal machining .

When metal framework is assembled onsite , such as aluminium frames for doors and windows in construction projects , it ’ s vital that the prefabricated pieces are delivered with holes drilled and pieces cut with precision . These projects demand speed of installation and if the framework includes inaccuracies or defects , this means time onsite to rectify the issue or the introduction of waste through rejects .
As a result , a key requirement for metal working machines from routers to drills is precise control and stability in the automation process to enable accurate positioning throughout the machine ’ s operation . Without consistent accuracy , this results in poor fit and finish of the completed framework that can impact the quality of construction and efficiency of build .
A major cause of inaccuracy in metal machining is deflection . A common problem when machining with high speed drills and routers on aluminium framing , as the material moves through the machine , the cutting axis can bite , bend or wobble . Crucial to avoid deflection , it ’ s imperative that the machine ’ s actuators securely hold the drill or withstand the force of the press to prevent misplaced drilling or cutting .
The more exacting the specification or intricate the operation , the more
crucial this becomes . If the actuator system can ’ t provide rigidity to sustain secure retention amid high paced machining , the pace of manufacture has to slow accordingly , impacting productivity . Alternatively , the machine risks inaccuracies and defects , affecting product quality and introducing waste .
To combat deflection , ideally the actuator requires a single body frame with a thick aluminium base , factors that contribute to high rigidity . Smooth action and control of the rail stage will also optimise control , and actuators specific to the task , such as Tolomatic ’ s TRS , provide high positional screw accuracy with the roller nut model providing ± 0.0102mm / 300mm .
Combined with a controller and its software program , a multi-axis approach to metal machining of prefabricated framework can increase productivity by speeding up production . On such an approach , material can be automatically moved into position . A three-axis linear actuator system operating across X , Y and Z planes of movement can drill and route the top , bottom and front sections . High-speed tool sets can be mounted on multiaxis actuator system and cut holes and shapes according to the controller and software with a 90-degree upcut saw cutting the product to the required size . Introducing Tolomatic ’ s TRS actuators can achieve a three-axis configuration , mounted carrier-to-carrier with no additional mounting plates required .
The generation of swarf and fine particles is an inevitable by-product of metal machining applications . To avoid this material entering and fouling the actuators and impacting their service life , adequate sealing is required . A retained exterior dust band will keep contaminants from entering the actuator interior , protecting components to provide reduced maintenance and increased uptime . In addition , positive pressure with air lines and filters will ensure that contaminants do not enter the interior of the actuator . Ideally , the body of the actuator should be constructed from fatigue and corrosion resistant stainless steel . The wiper and seal on the actuator ’ s rail stage surface should also be integrated into the carrier design to provide consistently smooth and controlled operation .
OEMs might have their own choice of motor to power the actuator and INMOCO ’ s engineers can also advise on the optimum combination according to the application ’ s requirements . Tolomatic ’ s TRS can be delivered with mounting hardware specific to the required motor with in-line or reverse parallel mounting . In combination with the actuation system , INMOCO can also specify control hardware and assist in the selection and development of motion programming to optimise throughput and control accuracy for the desired application .
Removing deflection combined with high positional accuracy will ensure precision cutting and drilling across metal machining applications . Adequate sealing and protection of the actuator system will not only ensure smooth , service free operation , it will also reduce the total cost of ownership and enhance the lifetime of the machine .
www . inmoco . co . uk