Why In-Die sensing is a must

Metalforming suppliers are facing unprecedented challenges in today’s marketplace. As capital becomes scarce, and competition for business increases, the impact of a die crash or production run of bad parts could make the difference in whether they survive. Companies must protect their most critical assets, the presses and dies. Presses, dies, and various press room automation systems are the lifeblood of the supplier, and their costs can run into multiple millions of dollars in capital investment.

Sensor-driven error-proofing and die protection programs reduce downtime, ensure production is maximized, and prevent costly capital equipment repairs. Sensor implementation can prevent most die crashes and defective parts production if utilized correctly.

The vast majority of expensive press and die damage occurs due to failure to implement or the misapplication of sensing devices through a die protection program. There is a relatively inexpensive way for metal formers to protect their most critical assets in terms of dollar value and revenue creation. Stamping companies need to focus on two main areas to reduce costly repairs and production:

Feed-in and feed-through: You have to ensure the metal is in the press before the start of the cycle, and that it is feeding through properly. Once the cycle has completed, you must make sure the finished part is out of the stamping area. The type of stamping you do will determine the various points where you will need to incorporate sensors.

Part and slug ejection: During the stamping process, scrap material will be left that needs to be removed before the next cycle. Failure to ensure this will leave material inside the press, which can affect product quality or cause significant damage to the press, die, or both.

There are multiple additional processes within the press operation that can improve overall operational efficiency, but the two above should be the first steps toward implementing a successful program.

Multiple sensing devices can help you meet these requirements as well as a variety of suppliers and options you can choose from. It is essential that your personnel are trained on the various sensor technologies, and you are aligned with a supplier that understands the industry, your processes, and the variety of dies and materials you produce.

Many suppliers can provide you with sensing parts, but only a few are industry experts and can serve as both a consultant and parts supplier. You may need to invest a little more to get the expertise necessary to implement a sensing program upfront. Still, it will pay dividends for years to come if you focus upfront on the products that will reduce the downtime related to premature component failure or misapplication of sensor components.

Also, since most suppliers outsource the design and build of their dies, it is critical that your sensor solution partner is involved in new die design, with both your internal team as well as your die supplier. In addition, successful die protection programs entail rigid specifications for die sensing to help reduce their spare parts footprint and maximize the performance of their sensing devices.

 

Sensor Reliability in Steel Production

01_SteelIn any continuous manufacturing process such as steel production, increased throughput is the path to higher profits through maximum utilization of fixed capital investments. In order to achieve increased throughput, more sophisticated control systems are being deployed. These systems enable ever-higher levels of automation but can present new challenges in terms of managing system reliability. Maintenance of profit margins depends on the line remaining in production with minimal unexpected downtime.

It is essential that control components, such as sensors, be selected in accordance with the rigorous demands of steel industry applications. Standard sensors intended for use in more benign manufacturing environments are often not suitable for the steel industry and may not deliver dependable service life.

When specifying sensors for steel production applications, some environmental conditions to consider include:

Heat

High-temperature M30 proximity sensor.
High-temperature M30 proximity sensor.

High temperatures exist in many areas of the steel-making process, such as the coke oven battery, blast furnace, electric arc furnace, oxygen converter, continuous casting line, and hot rolling line. Electronic components are stressed by elevated temperatures and can fail at much higher rates than they would at room temperature. Heat can affect sensors through conduction (direct transfer from the mounting), convection (circulating hot air), or radiation (line-of-sight infrared heating at a distance). The first strategy is to install sensors in ways that minimize exposure to these three thermal mechanisms. The second line of defense is to select sensors with extended temperature ratings. Many standard sensors can operate up to 185° F (85° C) but high temperature versions can operate to 212° F (100° C) or higher. Extreme temperature sensors can operate to 320° F (160° C) or even 356° F (180° C).

Don’t forget to consider the temperature rating of any quick-disconnect cables that will be used with the sensors. Many standard cable materials will melt or break down quickly at higher temperatures. Fiberglass-jacketed cables, for example, are rated to 752° F (400° C).

Shock and Vibration

Hydraulic cylinder position sensor rated at 150 G shock.
Hydraulic cylinder position sensor rated at 150 G shock.

Steel making involves large forces and heavy loads that generate substantial amounts of shock under normal and/or abnormal conditions. Vibration is also ever-present from motors, rollers, and moving materials. As with heat, look for sensors with enhanced specifications for shock and vibration. For sensors with fixed mountings, look for shock ratings of at least 30 G. For sensors mounted to equipment that is moving (for example, position sensors on hydraulic cylinders), consider sensors with shock ratings of 100 to 150 G. For vibration, the statement of specifications can vary. For example, it may be stated as a frequency and amplitude, such as 55 Hz @ 1 mm or as acceleration over a frequency range, such as 20 G from 10…2000 Hz.

Don’t forget that the quick-disconnect connector can sometimes be a vulnerability under severe shock. Combat broken connectors with so-called “pigtail” or “inline” connectors that have a flexible cable coming out of the sensor that goes to a quick-disconnect a few inches or feet away.

Mechanical Impact

Steelface proximity sensors bunkered in protective mounting.
Proximity sensor bunkered in a protective mounting block.

The best way to protect sensors from mechanical impact is to install them in protective mounting brackets (a.k.a. “bunker blocks”) or to provide heavy-duty covers over them. When direct contact with the sensor cannot be avoided, choose sensors specifically designed to handle impact.

Another strategy is to use remote sensor actuation to detect objects without making physical contact with the sensor itself.

Corrosion and Liquid Ingress

In areas with water spray and steam, such as the scale cracker on a hot strip line, corrosion and liquid ingress can lead to sensor failure. Look for stainless steel construction (aluminum can corrode) and enhanced ingress protection ratings such as IP68 or IP69K.

When All Else Fails…Rapid Replacement

Quick-change prox mounts for proximity sensors.
Quick-change prox mounts for proximity sensors.

If and when a sensor failure inevitably occurs, choose products and accessories that can minimize the downtime by speeding up the time required for replacement.

Strategies include quick-change sensor mounts, rapid-replacement sensor modules, and redundant sensor outputs.

In the case of redundant sensor outputs, if the primary output fails, the system can continue to operate from the secondary or even tertiary output.

You can learn more about sensing solutions for the Steel Industry in Balluff’s industry brochure.

“Gorilla” Warfare in Metalforming – How to Couple Stamping Die Segments Without a Hard Wire Connection

This post will show how to couple stamping die segments without a hard wire connection, AND prevent the potential gorilla-like effects of forklifts during die change! Have you ever experienced or heard about a forklift removing a stamping die with the giant Mil-Spec connector still attached (OOPS!!!!)? It certainly isn’t a pretty sight. Below is a typical Mil-spec connector, they aren’t cheap or easy to re-wire.

Or, have you ever tried to figure out a way to add sensors in very complex progressive die segments that will facilitate rapid die change?  If so, I have an answer for you with a non-contact connector system. Take a peek at the picture below.

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Implement Hassle Free Tool Changes

The Problem

From conversations with many of our customers, I have found that there are two key problems encountered when working with tool change-outs:

  1. Tool Identification:  “How do I know I have the right tool in there for the right job at the right time?”
  2. Cables & Connectors:  “How do I remember every time to disconnect them before the tooling is removed?  We spend thousands each year repairing dies with the cordsets torn out.”

Continue reading “Implement Hassle Free Tool Changes”