- Created: 2017-10-10
Learn the ins and outs of replaceable insert tooling designed to reduce waste and increase efficiencies
by John “JJ” Johnson, punching product manager, Wilson Tool International
Cost and quality are two of the driving forces when purchasing tooling. The lowest cost often equates to the lowest product price, but often that mindset can compromise quality and the life of the tool. To gain the quality benefit out of tooling investments, sheet metal fabricators are starting to think more in terms of the cost of ownership versus the cost of the tool.
Cost of ownership incorporates a number of factors, including the price of the tool and beyond. Characteristics inherent in all production operations, such as frequency of tool sharpening and changeover, number of hits per application, flexibility between long and short runs, tool waste in the form of breakage and wear, and numerous other variables play a significant role in determining the value of a tool beyond the initial purchase price.
Replaceable insert tooling for punches and dies help mitigate daily challenges faced by fabricators when it comes to making smart tooling investments. By identifying these variables and assessing the unique challenges of individual shops, sheet metal fabricators can determine if replaceable insert tooling is right for their shop and make the best decisions on how to integrate it into daily operations.
Designed as a two-part system, replaceable insert tooling features a holder and a perishable insert. The perishable insert typically accounts for 20 percent the cost of the tool while the holder makes up the remaining 80 percent. The concept is that fabricators invest in the system, so that when worn or broken punches require replacement, the only cost involved is purchasing a new punch tip or insert rather than an entirely new tool, which can provide a savings of 30 percent or more.
Most tooling manufacturers offer punch and die replaceable insert tooling available for thick and thin turret stations, Trumpf and Salvagnini style. The tools are usually available for numerous types of applications, including standard hole punching, parting, cluster, countersinking and others.
Trumpf’s style of replaceable insert tooling, for instance, is designed so the inserts deliver twice the grind life compared to other replaceable inserts by including a spacer for the punch. When inserted into the punch holder, the spacer raises the punch tip, giving the punch an additional 3 mm of grind life, saving manufacturers time and money while also reducing waste.
Cost of ownership
Lower tooling prices and higher quality tools are two of the most persuasive values when considering cost of ownership. The smaller insert has a lower replacement cost than purchasing an entirely new, full-body tool. The smaller size also allows tooling manufacturers to use higher quality tool steels. Fabricators gain longer tool life, but at a lower price point compared to a full-body steel tool.
The higher strength steel of the punch holder also delivers higher shock and fatigue resistance in heavy-tonnage applications. In these instances, the holder can be made from higher shock resistant steel, which helps reduce the chance of breakage.
As well as lower prices and higher quality tool steels, replaceable insert tooling systems deliver greater flexibility on the shop floor. High-hit applications, in particular, benefit from more hits between sharpenings and faster, easier changeovers when only having to change inserts versus entire tools.
One example of replaceable insert tooling with easy changeover features a lock-and-key design. In this setup, operators simply place the insert or punch tip into the holder, then lock it into place using a hand-held key. To remove, unlock the insert and remove it from the punch.
Lean practices come into play when considering the cost of ownership of replaceable insert tooling, as well. Replacing inserts rather than entire tools leads to less waste, and less time needed for changeovers reduces labor needs and increases available time on the shop floor. More time between part runs allows for more efficient production schedules and the opportunity for more timely completions.
Making alterations in tooling naturally brings changes to overall production, and replaceable inserts are no exception. Because they might not be the best choice for all operations, it’s important for sheet metal fabricators to determine how their shop might be limited or challenged by implementing replaceable insert tooling and how to identify and address those challenges to make an informed decision.
Due to the tooling design, not all replaceable insert tools offer a quick-change option. Therefore, they may not deliver time savings to all types of fabricators, especially those running short part runs that require frequent changeover. At the same time, operators may be resistant to disassembling and reassembling the inserts and holders and see it as a liability rather than an asset to shorter runs.
Replaceable insert tooling is available from many tooling manufacturers, but choosing to implement a system may lock a fabricator into working with just one manufacturer. While the holders are compatible with all types of punch press assemblies, most manufacturers’ holders are not compatible with other manufacturers’ inserts and vice versa. This could be a benefit if the fabricator has a long-standing relationship with a specific tooling manufacturer, but a limitation if they prefer to buy tooling from multiple sources.
Implementing major tooling changes into regular production can be daunting – especially if operations seem to be running smoothly. By evaluating the benefits and limitations of replaceable insert tooling, fabricators will have an easier time making the best choice for their shop.
Often, the best place to start is a conversation with the tooling manufacturer. These individuals can assist fabricators in making decisions by answering questions and discussing applications in detail. These conversations can bring to light any potential pitfalls before making considerable changes.
Once the decision has been made to implement replaceable insert tooling, starting small is often a good way to begin. Trying out a set of replaceable insert tooling for a few short-run jobs can help fabricators determine the return on investment before outfitting the entire shop. Trial runs, informed decisions and understanding operational challenges are all assets for fabricators as they explore replaceable insert tooling and find valuable means for increasing uptime, adding flexibility to operations and increasing revenues.