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When an automatic screwdriver is paired with a robot or linear slide, productivity can take off.
In the spectrum of screwdriving automation, a semiautomatic screwdriving cell might seem like a compromise.
Certainly, using a handheld autofeed screwdriver to install screws is dramatically more productive than manually picking up a screw, inserting it into a part, and driving it home. On the opposite end of the spectrum, screwdriving operations are easily integrated into a multistation automated assembly system, as long as the production volume and expected product life cycle warrant the large capital outlay.
So when does it make sense to invest a semiautomatic screwdriving cell? "Any part with a good population of screws would be a candidate," says Jack Keady, business development manager at Assembly Automation Industries. "Six to eight screws per part; 5,000 to 6,000 screws per shift. You want speed. If the parts will be manually loaded, you want the cell to be faster than an operator assembling the parts and installing the screws."
"A semiautomatic screwdriving cell buys you half an operator's time for free," adds Jim Graham, president of Weber Screwdriving Systems Inc. "Whenever they're not loading or unloading parts, they can be doing other tasks. They can be doing preassembly, labeling, packaging-a lot of secondary tasks can happen during that 'quiet phase' while the cell is installing screws."
Quality and consistency are other reasons to invest in a semiautomatic screwdriving cell. "With people, there's more variability in process control," says Graham. "With a screwdriving cell, you can be sure that all the screws were installed and that torque, angle and depth specifications were met. And, you can export all that data for traceability."
Indeed, a need to increase product quality was the primary motivation behind one company's decision to purchase a screwdriving cell from Visumatic Industrial Products.
"The part had deep pockets for the screws, as well as openings for other functions," recalls Jarrod Neff, marketing manager at Visumatic. "If an operator dropped a screw, it could fall into one of these openings. An autofeed screwdriver mounted to a robot solved the problem."
On the other hand, a semiautomatic screwdriving cell may not be the best option for high-mix production.
"Manufacturing is trending toward small batches," says Graham. "The...