drive&control local - Bosch Rexroth
drive&control local - Bosch Rexroth
drive&control local - Bosch Rexroth
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AUTOMATION<br />
20<br />
drive & <strong>control</strong> <strong>local</strong><br />
A new spin on<br />
welding plastic parts<br />
Plastics power welder uses <strong>Rexroth</strong> drive, <strong>control</strong> and linear motion technology<br />
The traditional image of welding involves large pieces of metal<br />
and sparks flying as the welder applies the torch. However,<br />
welding small plastic parts involves joining them by pressure<br />
and friction in a precisely <strong>control</strong>led automated process. One of<br />
the most challenging of these welding tasks is the production of<br />
fluid-filled plastic balance rings, used in balancing the wash load<br />
in a washing machine.<br />
Most balance rings begin life as two donut-shaped plastic pieces<br />
(about two feet in diameter), one of which is held in place while<br />
the other half is spun and pressed downward onto it. The<br />
compression force and friction melts the plastic to exactly the<br />
right extent, forming a leak-proof weld.<br />
When one major appliance part fabricator recently found itself<br />
experiencing an unacceptably high level of wasted materials<br />
and scrapped parts it called upon machine builder Eagle<br />
Technologies. With guidance from <strong>local</strong> <strong>Rexroth</strong> automation<br />
distributor Morrell Inc., Eagle Technologies chose a total<br />
solution from <strong>Rexroth</strong> including drive, <strong>control</strong> and linear motion<br />
packages, including IndraDyn servo motors and IndraMotion<br />
MLD integrated motion logic <strong>control</strong>, as the most flexible and<br />
cost-effective solution for dealing with the unique challenges.<br />
The drive-based <strong>Rexroth</strong> IndraMotion MLD integrated motion<br />
logic <strong>control</strong> platform is a SERCOS III Ethernet-based system<br />
used in the Eagle Technologies plastics spin welding machine<br />
(which welds parts together by using high-speed friction). This<br />
eliminates the need for a separate PLC and combines motion and<br />
PLC functions in a single automation platform. The motion logic<br />
<strong>control</strong>ler works with <strong>Rexroth</strong>’s IndraDrive digital intelligent<br />
servo drives and IndraDyn S motors to drive the spin welder,<br />
and allows precise <strong>control</strong> of low-speed, high-torque spin<br />
motion. Using the <strong>Rexroth</strong> HMI, operators can apply a full menu<br />
of parameters for each welding operation: motion, positioning,<br />
force, power usage and more. Changes to parts configurations<br />
and welding parameters can be accomplished through the<br />
touchscreen, instead of reconfiguring the entire machine.<br />
“Usually a weld machine design starts with a PLC and then the<br />
designer builds out from there,” says Earle Cooper, project<br />
manager for Eagle Technologies. “<strong>Rexroth</strong>’s IndraMotion MLD<br />
lets us start with <strong>control</strong> of two axes already built into the servo<br />
drive, so we could focus on a wide range of options for creating<br />
different types of welds and parts.”<br />
The end-user realized an immediate<br />
improvement in the efficiency and<br />
productivity of their balance<br />
ring production.<br />
Scrap material dropped from 15 percent to less than one<br />
percent. The machine’s HMI repeats the parameters of a perfect<br />
weld and spin profile, time after time. These improvements have<br />
been incorporated without compromising productivity or<br />
operator safety. <strong>Rexroth</strong>’s Safety on Board drive-based machine<br />
safety system uses Safe Motion technology to maximize operator<br />
safety in cases where the operator must reach into the weld area.<br />
(The safety system conforms to EN954-1 Category 3 safe and<br />
supports new ISO 13849 standards).<br />
Contact: Kevin Gingerich<br />
Email: kevin.gingerich@boschrexroth-us.com