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Innovative manufacturing with Tebis

Creative mold manufacturer Schweiger in Uffing (Bavaria) developed an injection process for hollow body manufacturing. This procedure, which won the gold EuroMold Award, not only conserves resources but is also notable for its high cost-effectiveness.

The tool and mold manufacturer Schweiger in Uffing received the gold EuroMold award for developing the innovative PIT process for manufacturing complex hollow ready-to-install components.

Erich Schweiger founded this company – specializing in tool and mold manufacturing – in a converted barn in 1962. Pure determination has made what began as a one-man company with just one lathe into a highly respected partner in the automotive industry that is sought after for its complex plastic molds and intelligent solutions, and is the recipient of many awards. The 65 highly qualified employees – 40 experienced mold and die makers, eight designers and four programmers – ensure the necessary process throughput for the company. The operation boasts eight modern machining centers, a variety of turning, grinding and EDM machines, two injection-molding machines, an in-house heat-treating facility and seven Tebis workstations (although in the opinion of managing director Anton Schweiger, they need still more). Work preparation is the driver and control center of the company, initiating and controlling all processes – from programs through planning and process reliability to on-time product completion.

  • Roughing in unattended shifts

    This is the only way to enable up to 5,500 active operating hours on the machining centers. During the staffed shift, the specialized and delicate tasks are processed flexibly and the machines are set up for the unattended shifts. "We do unattended roughing,” says managing director Schweiger, and he continues: "Collisions have become very rare: first of all, because the blanks are preprocessed far more accurately and are more homogeneous in their structure than in former days; but also because our programs are becoming more accurate. My highly qualified employees are very important to me, and they really don’t like to be stuck in the shop at night. Orders are always processed in the timeframe agreed upon with our customers. This is one of our principles – and we stick to it."

  • Complex and demanding molds

    Molds for hollow bodies like cooling-water pipes have been manufactured by Schweiger for the so-called GIT (gas injection technology) process since the mid 1990s. In this process, the still-pliable inner phase is pressed by gas pressure from the parison where the walls are already solidified. Improved interior surfaces and faster cool-down times were soon attained with the WIT (water injection technology) process. The "W" here stands for water.

  • Projectile-driven in the opposite direction

    Two years ago, an idea was floated at Schweiger: to calibrate the irregular, rough, and difficult-to-control inner diameters and irregularly thick walls using a projectile driven by water pressure. This was the first conceptual step. The second step was even more important. Until that time, a water injector was used to press the still-pliable plastic in the center of the hollow body away from the heating channel into an overflow. This caused significant loss of material and increased the cost of handling and recycling. The idea was now to reverse the direction of injection and to recover the plastic core through the runner head and the hot runner in the screw. The displaced material (80 to 175 percent of the final component weight) is not pressed into a secondary cavity (overflow), as per usual, so it can now be reused in the next injection process. The calibrating projectile is stopped just before the runner head.

    A highly efficient tool solution will get you more than you could save with an inexpensive one," managing director Schweiger says in discussing the benefits of his new tubular "hardware."

     

  • A multitude of benefits

    By combining these methods, a very economical and environment-friendly procedure is established for manufacturing hollow bodies. In the newly developed PIT process (where the "P” stands for projectile), the plastic material is not pressed into a secondary cavity; and so a significant savings potential has been created in terms of the consumption of the raw material compared with traditional procedures. Additional material can be saved by creating thinner walls, which can also be reproduced more reliably than in the standard GIT and WIT processes.

    The PIT process (on the right) provides very even wall thickness and inner diameters compared with the traditional WIT (on the left), as well as significantly reduced material consumption – because no plastic material is lost and expensive reconditioning is eliminated.

  • Tebis, the pillar of our processes

    Schweiger has relied on software from Tebis for CAD/CAM since 1990. Fourteen different Tebis modules are currently in use at seven workstations in Uffing, ranging from CAD Basis to Viewer. "In our company, Tebis is a pillar of our process reliability. We are currently strengthening this pillar by expanding our shop with even more focus on the Tebis system, in order to further improve our automation and process reliability," says Schweiger, who relies entirely on Tebis for machining and non-machining processes. From roughing to 2.5D drilling and milling to 5-axis HSC machining, all NC programs are generated using Tebis. Maximum productivity is achieved at the machines for wire and sink EDM as well – thanks to upstream Tebis stations. Now Schweiger wants Tebis Consulting to help support their automation in the NC area by implementing the Proleis manufacturing data management system. Proleis is a PDM system that captures all information, data and documents required for the manufacturing process from all departments involved in the production chain. These data are displayed and managed transparently and in detailed production structures – directly on the user interface of the Tebis CAD/CAM stations. The PDM system is operated by the employees in their usual environment, which significantly simplified the introduction of the software.

    The major portion of value creation occurs in the actual manufacturing. Any company that can ensure high machine utilization – as Schweiger Formenbau does – will be well-positioned for the future. With Tebis, Schweiger has not only attained a high degree of automation, they are also fulfilling the company’s philosophy about performing work that protects their valuable human resources and ensures process reliability. "We want just one partner in manufacturing,” explains Schweiger. "Working with Tebis, we attain a high degree of machine utilization and planning reliability, and we have an end-to-end software for all of our technology."

Overview

Quote

In our company, Tebis is a pillar of our process reliability.

Features

Focus:

Automated and reliable end-to-end manufacturing

Benefits:

  • Perfect NC programs
  • Full utilization of machine capacity, unattended manufacturing
  • Extremely high degree of on-time delivery

Sector:

Mold manufacturing, Automotive

Company:

Schweiger GmbH & Co. KG

Location:

Uffing, Germany

Interviewee:

Anton Schweiger

Position:

Managing director

Published:

2011

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