Designing for repeatability

Steel processing shops are continuously pressured with demands for better delivery, improved quality and tighter tolerances. Tooling plays a major role in accommodating these market-driven demands.

The steel processing fabrication shop, like virtually all metalworking businesses, is faced with seemingly relentless pressure on its margins. Customers of all shapes and sizes are swinging the cost-cutting axe with a vengeance. Processing shops find themselves squarely in the path, whether they are jobbing or regarded as a production business. Suppliers to these businesses are also in the firing line, whether you are a consumable supplier or a press tool supplier.

TDS Engineering is one of very few South African companies that offer end-to-end press toolmaking

TDS Engineering have been producing tools for a variety of industries since 2007. Owned and run by sole member Gary Pierdica the company has supplied tooling to a wide range of industries, from automotive to mining, roofing, steel profiling, and appliances, among others.

Pierdica is a toolmaker and only started his own business at the age of 42. Prior to that he worked for one of the bigger companies in South Africa that was supplying product to the automotive OEMs.

“I worked for GBG Engineering for 17 years, completing my apprenticeship with them, before they were acquired by Benteler Automotive in 2003. I worked for Benteler for a further four years. At the time South Africa’s automotive industry had been one of the turbo chargers behind the country’s growing export and manufacturing sectors. Some of the world’s most recognised automotive brands call South Africa their home and of course this means that the need for a high-quality, superior class supply chain has developed.”

“One of the companies providing pioneering innovation in this field is Benteler South Africa, the local subsidiary of the global steel and aluminium manufacturer, headquartered in Austria, Benteler International AG.”

“Benteler arrived in South Africa in 2003, taking over GBG Engineering with pressing facilities in Alrode. After establishing its roots in South Africa, the company immediately went about expanding its footprint, bringing its facilities in Alrode in line with modern standards and also opening up in the home of South Africa’s automotive sector – Port Elizabeth in the Eastern Cape.”

TDS Engineering design intricate manually fed and progressive press tooling

The surface grinding department

“I was fortunate enough to be part of the Alrode upgrade that was equipped with high-tech equipment and systems. Prior to the takeover I had been recognised by GBG Engineering management and was promoted first to foreman and then to Toolroom and Design Manager. Besides manufacturing the tools on the machines I also got involved in designing, learning how to use the high-end software required to design intricate manually fed and progressive press tooling.”

“I had five years in this position and a further five years concentrating only on designing in the position of Design Office Manager before I decided to leave and open up my own company. Benteler is an international brand. World leading technology is developed at Benteler around the globe by its research and development teams. With additional feedback from all of the other additional manufacturing subsidiaries worldwide, Benteler South Africa was assured of using best practices locally. I was part of this experience and the knowledge I gained has been invaluable.”

“My association with Benteler also resulted in the company being my first client when I started my business and they are still one of my most important clients.”

Small beginnings
“I started off small – on my own renting some floor space from an engineering company in Alrode. However, today the company has grown to the extent that I now employ 16 staff and we occupy a
1 000m² building in Alrode South. We also have six CNC machining centers, CNC wire cutters and spark eroders, surface grinders and other equipment associated with the various processes in our industry, including a number of milling machines. Making tool/die sets and mould components calls on most metalworking disciplines. Milling, EDM and grinding all come into play.”

One of the bigger Takumi CNC machining centers on the floor. The company can machine blocks up to 2 000mm by 1 060mm travel

A Takumi CNC vertical machining center

“TDS Engineering is one of very few South African companies in our field that offer end-to-end press toolmaking. In other words we offer a complete press tool solution, encompassing in-house design to the manufacturing of the press tool.”

“However, it is not just the precision press tools that we design and manufacture. We also design and manufacture the accompanying jigs and checking fixtures for our customers, if they are needed.”

“Most of the more recent improvements in CNC technology have been focused around the need to improve productivity. While much effort has been directed to making the machines go faster, thereby reducing cycle time, additional consideration has been directed to looking at time savings across the entire fabrication process. Industry 4.0 is great example.”

“These innovations have been demanded by shops, and original equipment manufacturers are responding to their customers’ demands for shorter order turn around, tighter tolerance specifications and delivery that coordinates with just-in-time inventory control systems.”

TDS Engineering also has a Victor Vcenter 4 CNC machining center with a table size of 580mm by 440mm on the shopfloor

The Kafo vertical machining center

“Moreover, advancements in the simplification of manufacturing, with the use of CNC and user-friendly programming systems, has helped shops respond to the shortage of qualified workers. Many of the skills traditionally required to set up and operate presses are being incorporated in software and hardware that is designed to simplify the operation.”

“Likewise in tool design. As a tooling designer, you must design in the maintenance process. If you don’t, how will you know it can be done accurately and repeatably? You must design the die so that all cutting and forming sections cannot be put in reverse, backwards, or upside down. If a punch can be shimmed to the point at which it interferes with other tooling, then you need to put maximum shimming instructions on the component print. Don’t assume the service technician will figure it out.”

“All purchased components, such as springs, screws, dowels, keepers and shims must be designed or specified out. The tool builder and toolroom should not have to guess at your intentions.”

Design out people skills, design in machine capabilities
“Machines make components, and people maintain them. Skill levels vary. Do not design components that require a highly skilled maintenance worker to ensure repeatability. Today’s wire electrical discharge machining (EDM) can deliver the accuracy and surface finish required. Put those requirements on the print. Spell out surface finish if polishing is needed and corner breaks where required. No exceptions. Design in repeatability, and remember the three R’s: Repeatable, reliable, replicable.”

Design for zero development
“Success is based on understanding what to expect from each station in the tool. In tool development, if something is done twice, you didn’t achieve the objective the first time. Design to meet capability requirements. Get input from the people who run the tools. This is one of the single largest factors that affect the success of the design process. Look at similar existing stamping tooling and its output relative to the design and product dimensional stability.”

TDS Engineering have clients that are tier 1 and tier 2 suppliers to the automotive industry

TDS Engineering have two presses to test the progressive dies they manufacture

“Plan on facilitating development by anticipating what can go wrong, and design in risk mitigation. For instance, add inserts where they might need to change. Add extra pilots if there is a concern that the strip might be pulled during heavy coining or forming. Have an idle station in the tool in case it is needed later.”

“In a progressive tool, coils of sheet metal are fed between the upper and lower halves of the die set. Each time the press closes, a complete part is ejected at the finish end of the press.”

“A progressive tool may have two, four or even 16 different stations to generate a complete stamping. After the press completes a stroke, the coil feeds from one die station to the next. Some die sets are designed to progressively stamp a flat shape and then fold the stamping into a 3D part. This is all done in one press on one progressive die.”

“Benteler offer customised solutions for a broad range of products in the safety, environmental and efficiency sectors. Integrated lightweight construction is the main focus of their widely diverse activities. Products include components and modules for the chassis, body, engine and exhaust systems. They could be hinges and brackets for catalytic convertors to dashboard carrier panels to front and rear bumper components.”

“We therefore have to be constantly upgrading our equipment and the facility to meet their exacting requirements. That is why we have recently added another Takumi CNC machining center and a Fanuc wire cutter to our machinery list.”

One of the recent machines acquired is a Fanuc Robocut Wire EDM

The company also has a Chmer Wire EDM and another Fanuc Robocut Wire EDM at its disposal

“I might be mentioning Benteler frequently. That is because they are our benchmark and most important client. However, we are not restricted to them. At the moment we are manufacturing tools for one of the leading South African companies in automotive metal stamping. They have a press shop with 69 presses in it that range from 50 to 1 300 tons.”

“We also have other clients that are tier 1 and tier 2 suppliers to the automotive industry and those that are supplying the rail, construction, steel profiling and mining industries.”

“A progressive tool is a complex tool that doesn’t just stamp a part by hitting it once, but instead cuts and forms the component in stages as the coil moves across it. Some progressive tool varieties have seen price declines and the biggest part of the reason for this is, of course, China.”

Dies to be assembled and tested

More dies in various stages of manufacture

“Overseas competitors have disadvantages they cannot get around. Labour costs might be low, but they still have to factor in the cost and delay of long-distance shipping. They also are limited by the long-distance and cross-cultural communication problems that can pose significant impediments to making an intricate tool (a tool that consists of various precision-machined parts) according to the customer’s literal design intent. They also cannot offer after sales support like we do.”

“When you are manufacturing tooling that uses high-grade steel and could weigh a few tons and more you don’t have an opportunity to re-melt the casting in a furnace and make the casting again like they do in in a foundry.”

“However, skilled labour remains vital. Skilled toolmakers are essential for every complex tool the shop produces. Experience does count but even I have studied further to improve my skills. Fortunately I have others around me who are also highly skilled, as all of our toolmakers have been trained in house.”

Keegan and Gary Pierdica

“Within my company I also have my son – Keegan – employed who has been working on CNC machines since he was 13 years-old. As a result, he passed his toolmaking trade test with ease.
Now at 26 years of age he runs the CNC shop, amongst many other things does all the programming for the six machines, and also assists with tooling design.”

A die being machined on another one of the Takumi CNC machining centers

“Die and mould components need to have high dimensional accuracy and excellent surface finish. Progression tool manufactured components call for the same high standards. Therefore, we have to produce tooling that is not stipulated but required.”

For further details contact TDS Engineering on TEL: 011 868 5070 or visit