In ideal situations, every workpiece is clamped perfectly to a custom-built fixture, mounted on a machine tool dedicated for such operations. And each workpiece is dimensionally identical, ensuring consistency and accuracy throughout every piece. Each and every fixture would be completely automatic, therefore positioning, clamping, machining, inspecting, and releasing the part with great precision. All this, however, is only in a perfect world without the limitations many face. Manufacturing and machine shops are constrained by many factors such as time, money, space, and labor. On top of this, our machine tools are commonly multi-use, not dedicated.

Purpose-built fixtures are not the industry norm, and setup is often a manual process. Plus, our workpieces have many variations, such as being oversized, undersized, or parting-line shifted. So, to lessen these variations, we look for effective solutions in effort to work towards an ideal environment.

Challenges of Execution

Workholding by definition involves orienting and maintaining a workpiece in a fixed position for a tool to cut. With this brief look towards this process, it may sound simple. However, workholding becomes a very complex process as many factors and difficulties are involved. Criteria from size weight, and dimensional stability to position, clamping force, and cutting force are all important considerations of workholding. Not to mention the speed at which a part is changed and ready for the next. Fortunately, modern workholding technologies have been created to remedy these challenges. With these modern technologies offering a variety of options, determining the right workholding solution can be the next step and challenge, for not every piece of equipment is “standard”.

Development within Workholding

ROEMHELD North America of Fenton, Missouri, is a leading global provider of workholding solutions, supplying over 80 types of air and hydraulically powered workholding devices, precision machine vises, and flexible fixturing. David Vilcek, manager of workholding and assembly at ROEMHELD North America, emphasizes the importance of efficient workholding, particularly for high-volume manufacturing. His advice? Stick to the KISS principle—keep it simple and straightforward. Vilcek recommends starting with their zero point system, such as the Stark Zero Point System, which offers a quick-change interface to reduce setup and breakdown times significantly. With the Stark Zero Point System, operators can swap fixtures with ease, regardless of whether it's a mechanical, hydraulic, pneumatic, vacuum, or electric fixture. The design ensures a precise system by constantly pulling the fixture pallets down, fitted with position and part sensing technology.

ROEMHELD North America doesn't stop at zero-point systems; they also provide a diverse array of products, including quick die-changes, mold-changes, hydraulic workholding, assembly, and handling solutions. While most products are hydraulic, they also offer pneumatic and electric workholding systems with zero-point capabilities. Vilcek highlights their innovative approach, blending hydraulics and integrated electronics to offer real-time feedback for improved performance.

As Industry 4.0 advances, ROEMHELD North America is at the forefront. Their commitment to supporting these technological advancements ensures that customers have access to cutting-edge workholding solutions tailored to meet evolving industry needs.

Optimizing Economics

The manual transition of workholding for producing a new part can be time-consuming, typically taking between 20 to 30 minutes. This demands a skilled operator to ensure accuracy and repeatability in workholding. Considering this process recurs multiple times within an average workday, it becomes evident that valuable spindle time, crucial for revenue generation, is lost.

Hence, a simple Return on Investment (ROI) calculation for workholding involves determining the additional number of parts that can be manufactured per shift or day with the proposed solution. This is achieved by analyzing cycle times, including setup, machining, and changeover. Time saved in these cycles translates directly into increased spindle time, amplifying productivity and profitability. Moreover, other cost-saving factors such as reduced operator injuries, decreased scrap, improved finishes, minimized tool changes, and prolonged spindle and tool life can also be factored into the calculation.

David Vilcek from ROEMHELD North America affirms this perspective, noting instances where customers have experienced remarkable reductions in setup time, up to 90%, by transitioning away from manual setups.