Increase efficiencies in nesting applications with better parting techniques
April 20, 2017 - It’s a bread-and-butter operation. From smaller job shops to massive OEMs, just about all manufacturing operations regularly have some form of parting application loaded on at least one, if not multiple, punch presses at any given time. The process of nesting allows for easier part handling and efficient sheet utilization.
Alongside the efficiencies come challenges, however, such as excessive tool wear, creating clean straight edges, avoiding forms and machine clamps. Using traditional tooling can all negatively affect part quality, production speed and overall profitability. Fortunately, there are a number of solutions manufacturers can implement to reap all the benefits of nesting and minimize the challenges.
Make better parts, incur less waste
As any fabricator understands, there are many ways to perform parting applications. Parting can be achieved using traditional punch tooling, but this option can yield poor results. If manufacturers are in a bind and need to produce a part quickly, using traditional punch tools is often the choice. While the decision can save time in the short-term, chances are the parts will require secondary de-burring operations or increase the appearance of nibble marks and deliver lower quality parts.
Numerous types of parting tools exist to help manufacturers curtail the negative effects of using traditional punch tools for nesting applications. For example, HP Dura-Blade® and Dura-Die® are a parting tool combination designed for thick turret, Thin Turret Fab style and Trumpf style punch presses, which bring fabricators a punching option designed specifically for parting operations.
As a punch-and-die solution, the Dura-Blade and Thick Turret Dura-Die set brings together the punch tool with replaceable inserts. The Dura-Die insert is available for standard parting in C, D and E stations as well as close-to-clamp options for D and E punch press stations.
One particular feature of the Dura-Blade is that it is specially designed to support the punch tip with the stripper. This process of being fully guided supports the punch tip, which minimizes punch deflection. This can help reduce nibble marks and wear on the side of the punch and die. By supporting the punch right at the tip with a close fitting stripper, it doesn’t have excessive clearance that can cause the punch tip to deflect, which helps creates a sharper edge to the finished part. Also, having tools and machine clamps properly aligned with the machines is critical to producing a clean straight edge.
A second valuable characteristic of the punch-and-die solution is the special reliefs. The reliefs allow fabricators to punch closer to machine clamps and high forms, such as louvers. This feature helps fabricators use more of the material and minimize sheet waste. Naturally, the closer the punch can get to the clamps without causing damage, the more parts can be produced from each sheet of material.
Minimize wear and tear
As a standard tool in virtually all types punching operations, parting tools take a high volume of hits on a regular basis. This activity causes tools to wear down in a hurry, which often sets off a negative ripple effect, leading to downtime for sharpening tools and costs for replacing old or broken tooling.
Because tool life is such a critical component of parting tools and maintaining efficiency on the shop floor, the replaceable inserts of the punch-and-die solution are manufactured from a proprietary tool steel called Ultima. Along with tool steels, coatings are available to fabricators to prolong the life of these hard-working punch tools. In addition, the parting tool set features a quick-release stripper plate retention and a push-button adjustment system that allows for quick changeovers and adjustments when tools do require sharpening.
Tips for tabbing and parting
The design options for creating shake-apart tabs on a sheet of nested parts are virtually limitless. How fabricators decide on the type of tab encompasses numerous factors, such as personal preference, downstream operations required to complete the part run, the size of the tab, the weight of the material and many, many other considerations.
While wire tabs are often the most common, corner tabs, diamond tabs, dash tabs and countless other design options can give fabricators flexibility in determining the best tabbing option for their individual nesting applications. Multiple tab styles can be created simply by using various shaped punches and dies.
Punching overlap is a second consideration for increasing efficiencies in parting applications. Manufacturers can either shorten or lengthen the overlap during the punching process, depending on the application. When creating nested parts, the traditional process calls for overlapping hits. If operators decrease the overlap, then there is less punch deflection, which can help reduce nibble marks and tool wear. Determining the most effective level of overlap is somewhat of a trial-and-error process, but the time involved is worth the effort in the long run. Less wear and tear on the tooling and higher quality part edges are some of the benefits that can be gained by decreasing overlap.
Make it faster. Make it better. Make it more affordable for the customer. These are some of the core goals of manufacturers to stay competitive in an ever-changing industry. With quick changeovers, longer tool life, reduced downtime and more efficient punching, fabricators can take the bread-and-butter operation of nesting tabbed parts and gain greater efficiencies on the shop floor, which translates to greater productivity and a greater return on investment.
John “JJ” Johnson is the punching product manager at Wilson Tool International. He has worked for the global tooling manufacturer for more than 37 years.