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Partnership between motion control, cameras more than stands test of time

Ilene Wolff
By Ilene Wolff Contributing Editor, SME Media

Promess, Rockwell & Zeiss improve individual components

While cameras and motion control have worked in tandem for at least 15 years, their integration has improved because networks have gotten faster, more reliable, and more deterministic (i.e., nothing will interfere with a function that’s a priority).

With Rockwell Automation’s three new safe-speed safety functions, work doesn’t necessarily have to stop when there’s a jam or an error on an automated line.

As a result, the interoperability of the different components on a network has improved, said Nathan Turner of Rockwell Automation’s motion control unit.

Determinism is all about timing and location, he said: Something occurs on a manufacturing line and we know exactly when and where it happens. Because of the improved integration, we don’t have to worry about another component in the network interfering or causing a problem.

Advances in network integration have occurred at the same time cameras and their controllers have improved, Turner said. The controller-related software is much faster, and the cameras’ resolution (to determine color, angles, shapes) is better. Based on the enhanced inspection by the camera and advanced analytics, the system will determine if a part on a manufacturing line is good or bad.

“That increases your productivity, your throughput,” he said. “Your flexibility goes up, too, because one system can pick up more parts, more failures, more defects.”

Rockwell recently introduced safety functions that slow down a line instead of stopping it for intervention, along with a new module to coordinate third-party devices.

Other recent developments from other machine vision and motion control companies include powerful presses that work on the end of robotic arms, a more widely available hybrid cable that moves both power and data, and refined camera lenses.

Why stop if you can slow down?

In terms of new network technology from Rockwell, the company has added functionality to satisfy both production and safety when a line needs maintenance or an error needs fixing. The technology consists of a new, advanced set of safety commands that can be integrated as an option into its Allen-Bradley Kinetix 5700 servodrive’s ethernet-IP network.

Typically, if there’s some kind of jam or error on an automated line, you have to stop the whole machine for safety reasons to prevent harm or injury to a maintenance worker or the machine’s operator. “What we’re saying is, there are many applications where if you really look at it, you only need to stop because you don’t have an alternative, there’s either a full stop [or the line runs] and nothing in between,” Turner said. “With this network functionality we’ve created, you don’t have to stop the machine.”

Rockwell Automation’s new safe-speed safety functions, including ones that control direction, speed and position, can be implemented after a standard safety evaluation.

There are three new safe-speed safety functions, including ones that control direction, speed and position. A standard safety evaluation can tell where and when any of the safety functions might be employed.

A separate, new device from Rockwell, the Allen-Bradley Encoder Output Module, can also be added to the network to help coordinate third-party devices, such as a camera, a cooling device, a glue dispenser, and more. The output module works by sending location information about a workpiece on any axis of motion on a line, real or virtual, to the third-party device. This prevents the third-party devices from interfering with one another. It can also be used for robotic pick-and-place in a non-linear application.

“It’s just a way of knowing I’ve got something moving at me at a certain speed and position,” Turner said. “I’ve got no idea what that is until the encoding device tells me.”

Floating press enables new collaboration

Promess’ Integrated Backstop Presses (IBPs), consisting of a ballscrew driven by a servomotor and equipped with an array of force and position sensors, add a seventh axis as they work on the end of a six-axis robotic arm.

Once the robot maneuvers the press into position, it enters “float mode;” the X and Y axes are locked, but the Z axis moves up and down freely. In this process, the robot isn’t subjected to any additional force during press operations, making use of the robotic arm possible and enabling shops to buy the smallest robot needed for the IBP, saving them money.

“While the robot was completely capable of accounting for the weight of the press, almost no robot can account for the force which the press can produce,” Matt Rall, a Promess engineer, said. “By entering the float mode, that concern is eliminated, since the force is now going into the back stop.”

The press’ tooling can be anything that fits and keeps the press and tooling weight in the acceptable range for the robot—a steel plate, gripper, staking device, spring, etc., Rall said. Because the press is servodriven, the entire system is easily programmed and reconfigurable to handle a variety of different parts and/or operations.

“Development of the Integrated Backstop Press line was driven by customer requirements for a fully electric, fully instrumented press configured for robot mounting in flexible cells and other applications,” Promess President Glenn Nausley said in remarks prepared for the media. “One of our major challenges was to achieve extensive weight reductions to match the presses to existing robot capabilities. During the development phase, we spent a lot of time optimizing the design in order to meet our target weights.”

The company lightweighted the press by adding “flats” to the outer housing, which reduced the amount of steel; eliminated unnecessary features like a mounting flange and connectors; cut the motor’s weight by using smaller versions and increasing the gear ratio; standardizing on a smaller stroke; and designing components like motor mounting plates and hoods to be more form-fitting.

The IBPs are available in 3, 5, 8, 12, 20, 30 and 50 kN capacities with strokes ranging from 180 to 350 mm (~7–14″).

“Right now, I would say the IBP is being looked at more in the automotive industry, but automotive is usually the first in terms of manufacturing movements,” Rall said. “I imagine that, as this whole flexible manufacturing movement trickles down to other industries, we will start to see more people interested in the IBP technology.”

The IBP prototype was developed for a major automotive supplier to install valve seals in cylinder heads in a flexible cell. Other typical applications include pressing a bushing, seal or other component into an engine, transmission, or wheel and brake assembly.

Firm makes more servos smart

Six years after introducing its Hiperface DSL smart servodrive interface in 2011, Minneapolis-based Sick Inc. began licensing it to others in June 2017. It recently signed licensing agreements with two companies, and is in negotiations with others, a company spokesperson said.

The company hopes that by making the previously proprietary interface available to others, it will become the market standard, according to a press release.

The distinguishing feature of the Hiperface is its one-cable technology, which transmits motor feedback signals within the power cable. The hybrid cable functions at lengths of up to 100 m (328′); special processes and the application of pulse transformers ensure that the encoder signal is decoupled from disturbances created by the motor power cable cores. Eliminating the need for a motor feedback connector plug frees up valuable space, especially on small servomotors.

The continuous monitoring provided by Hiperface DSL has potential for improved economic efficiency in smart factories.

“With the abundance of information available, users can easily observe how the servomotor is performing,” Jay Johnson, national product manager at Sick, said. “They can judge if it is the correct motor/drive size for the application or if it would be possible to use a lower performance motor.

In terms of failure analytics, the use of built-in histograms speeds up the progress in finding the root cause. Chronicled metrics, such as speed, temperature, fault logs, and signal strength, are all readily available.”

Lenses make machine vision clearer

Because machine vision needs good “eyes,” Zeiss recently introduced five new lens focal lengths in its Interlock line for industrial applications: the ZEISS Interlock 1.4/50, 1.4/85, 1.4/25, 1.4/35 and 2/35.

The new lenses feature quick shutter speeds and capture exact data, which increases process efficiency and thus decreases costs, said Till W. Bleibaum, director of B2B lenses for Zeiss in Oberkochen, Germany.

“Since sensors are becoming bigger and cheaper [driven by the consumer market] and computing power increases, high-performance lenses become the bottle neck of precise and fast systems and data processing,” Bleibaum said.

The Zeiss Interlock lenses are available with either an F-mount, EF-mount or M42x1 mount, and are suitable for full-format sensors and 41 mm (1.6″) line scan sensors. The fixture for the lenses is equipped with multiple screws, enabling users to securely clamp the aperture and focus. This is particularly beneficial in production environments with machine vibrations, and it ensures that the images are in focus. The new focal lengths provide edge-to-edge sharpness, the company said.

“These lenses have low levels of distortion,” Bleibaum said. “This way you can measure different-sized objects from various distances with great precision.”

The lenses’ sturdy metal design is also engineered to withstand rough conditions, including crash tests in the automotive industry.

As the technology from Rockwell, Sick, Promess and Zeiss show, even though cameras and motion control working together may be a time-tested partnership, there’s still opportunity for improvements and innovation in the individual components in a manufacturing network.

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