The concept of ‘fail fast, fail often’ has both its critics and its advocates. While failure can be a significant turning point in a product’s design, no manufacturer really wants it to happen.
When Everstampi, an Italian specialist in moulds for the plastics sector, sought a new micro drilling tool, it understood that failure was to be expected. However, to its surprise, a solid round tools (SRT) microdrill from Sandvik Coromant failed neither fast nor often. In fact, the company has experienced just one single tool breakage.
Working in the plastics industry for more than 30 years, Everstampi designs, manufactures and tests moulds for small and medium-sized plastic details for a variety to sectors. Supporting industries including cosmetics, food and beverage, household cleaning items and pharmaceuticals, Everstampi guides its customers through every step of the mould and die process – from the presentation of mathematical models, drawings and prototypes, through to mould design, manufacturing and commissioning.
Everstampi sees automation as the future for mould makers and has made several technology investments in recent years. The company partners with leading CAD/CAM specialists including Autodesk, and TopSolid, and has made significant investment in its machinery. Its shopfloor is currently home to a host of cutting-edge equipment, including four milling machines, four turning centres, two rectifiers, four EDM machines and a drilling machine.
These choices have paid off, and Everstampi is now a leading manufacturer of high-volume injection moulds, with some of the shortest production cycles in the market. In October 2021, the company sought a new micro drilling solution to drill precise holes into a printing part component. Needing a resilient, reliable solution, it chose to invest in tools from Sandvik Coromant.
Micro drilling techniques are used to produce components such as medical devices and surgical tools, aerospace parts and consumer electronics. However, it’s not just the micro size of these components that presents a machining challenge. Manufacturers are also required to machine increasingly smaller products from notoriously difficult-to-machine materials, like stainless steel, ceramics and titanium. Delivering high surface quality while maintaining tool life is no mean feat.
On this occasion, Everstampi needed to drill holes in components made from ISO H material. Steels with a hardness of 53-54 HRC, like the type Everstampi was working with, are difficult to machine. The materials generate heat during cutting and are very abrasive for the cutting edge. While tool failure is never desired, working with such materials means it’s often expected.
“Honestly, our objective was to get the job done while breaking as few tools as possible,” says Colombo Edoardo, production manager at Everstampi. “We were aware of the complexity of needing to drill such a large number of tiny holes into such a hard material. If we broke several tool bits, we’d have been satisfied.”
It’s not uncommon for micro drills to exhibit short tool life, especially when machining tough workpieces. Therefore, the design, quality and type of coating of the drill must all be carefully considered if the tool is to live up to expectations.
Everstampi selected Sandvik Coromant’s CoroDrill 862 with GM geometry to solve its drilling dilemma. The tool is ideal for precision drilling, able to make holes from 0,30mm to 3mm in diameter. CoroDrill 862 supports machining in all ISO materials and is available in a wide range of cutting tools and lengths. Put simply, CoroDrill 862 can make a real difference to the quality of the finished product. But is the tool built to last?
Everstampi selected the tool in five different diameters, between 0.5 and 0.9mm, all with the ability to drill hole depths of up to nine times diameter (xD). Because Everstampi selected its tools without coolant supply, which would ordinarily aid chip removal, Sandvik Coromant suggested the company favour peck drilling for more effective machining.
“Peck drilling involves plunging the drill part way through the workpiece,” explains Fabio Capone, solid round tools specialist at Sandvik Coromant. “Ideally, you need to drill down no more than once or twice the diameter of the drill, then retract it to the surface. This action is repeated until the hole is finished. When there’s no use of internal coolant, as in Everstampi’s case, we advise this method of drilling as it aids the chip evacuation process, supports tool accuracy and prevents chip breakage.”
To Everstampi’s surprise, tool breakage was not an issue. In fact, it experienced just one broken drill after machining approximately 1.5m of hole per drill. “It’s not that we didn’t trust the product – in reality, it’s pretty unfeasible for a microdrill machining such a hard material to do so successfully and without significant breakage,” says Mr Edoardo. “To have just one tool break during such intensive drilling isn’t only fantastic, it’s near impossible.”
For their small size, microdrills are tasked with great responsibility. Making highly precise holes in some of industry’s hardest materials is no easy task. When Everstampi first searched for a new microdrill, failing fast and often was to be expected. But, using the CoroDrill 862, frequent tool breakage did not get in the way of productivity.