February 19, 2001
Efficiency, productivity, and quality are focal points for end forming operations, and many manufacturers are looking to automation to improve those dimensions of their businesses.
Global competition is driving companies to continually evaluate all phases of their manufacturing to locate potential improvements. Automating new or existing equipment many times is a focus for manufacturers that want to continue growing.
Autoloading systems that can integrate with the control system of a machine can benefit tube end forming, which often involves products with high-volume production runs. Efficiency, productivity, and quality are focal points for end forming operations, and many manufacturers are looking to automation to improve those dimensions of their businesses.
Most industries are experiencing difficulties hiring and retaining enough qualified people to run machines for existing production, let alone any new products. Automation has been gaining momentum for several years as a means to competing in a worldwide economy. The automotive sector has embraced automation for many years and continues to make rapid advances in this field.
Several factors must be considered when evaluating the automation of end forming equipment. They include:
1. Cost. Comparisons must be made between the costs of manually operating fabrication machinery and material handling versus the capital investments for automation.
2. Floor layout. Automation introduces additional equipment to the floor, but it also can alleviate some material handling and storage burdens. Potential customers should ask how many different parts an autoloader can run.
3. Product flow. Both functional and cell manufacturing systems can be automated. Functional manufacturing focuses on departmental product flow. Each step in production is divided into departments. On the other hand, cell manufacturing combines each step of the production process into one product line. The machinery in cells is dedicated to that specific product.
A key question here is, "How quickly can the machine be converted to autoloading and then back to manual operation?"
Manual Labor versus Automatic Operation
Manual Labor Market. Technology has advanced rapidly in the past decade, as is evident in almost any office or engineering department. Some areas of manufacturing have been automated completely with only technical supervision required.
Advances in technology and a shrinking labor pool have prompted many companies to consider automating departments or manufacturing cells. End forming traditionally has required one operator per machine. That notion is changing with the intensive competition for available workers.
Finding employees who are willing to work in a production job at wages that allow the company to turn a profit rarely has been a problem in the past. Low unemployment rates and strong economic growth have made it difficult to hire qualified people to work at industry-average wages. Wages and health-care costs continue to increase, putting pressure on the bottom line of labor-intensive companies.
Most manufacturing environments like their employees to run close to 80 percent efficiency. However, a three-shift operation with lunches, breaks, and shift changes creates a lot of downtime.
Automation. Equipping end forming machines with automated loading and unloading systems can boost efficiency to nearly 100 percent. That 20 percent increase results in a direct productivity gain.
For example, one operator can maintain production on several machines, depending on the difficulty of the end form and the capacity of the loading system. The diameter of the tube also affects loading capacity and the number of machines an operator can run.
Most systems are not designed to fit every style of machinery in a plant, but rather for a specific type of machine or machines. However, autoloading systems can be modified to work with many different parts and are adaptable to a few machines if the control systems and alignment are compatible.
Of course, an autoloading and unloading system requires financial investment. Depending on the part and process, it can be a significant initial output. That investment can be recovered quickly if efficiencies and productivity are improved, though. A detailed comparison must be conducted to calculate return on investment.
Manufacturers of large varieties of end forms down to just a few designs can use a product-oriented plant layout to increase efficiency. This strategy does not necessarily involve automated equipment, however.
A manager's goal usually is to arrange a layout or system that operates at peak performance. An efficient and effective system helps to optimize placement of machinery and personnel throughout the plant. Two approaches can be taken to move components through the production process—function-oriented layout or workcell manufacturing.
Function-oriented Plant Layout. A function-oriented layout organizes each step of the production process into individual departments. This system allows each department to focus on a specific function. For example, a cutoff department can specialize in cutoffs, end formers can focus on end forming, and so forth.
Each department should have several machines, which eases product flow through the department. A breakdown of one machine in a department should not stop the entire production line because work can be transferred to another machine.
This layout approach also benefits manufacturers that produce a variety of low-volume parts because tooling changeovers do not have to stop production.
Transferring material between departments is a disadvantage of this system. A lot of time and money are spent on material handling. Labor requirements and work-in-process inventories tend to be higher as well because of imbalances in the process.
With operations divided into departments, products are accumulated before they are moved to the next department. Moving products all at once may overload a department, especially if cycle times are slower in that department.
At times, a portion of a company's production staff is dedicated to moving and storing products among departments. Labor costs increase as personnel are assigned to transferring and monitoring material handling. Once material handling is completed, the dead time that products are sitting idle and waiting to be processed must be minimized for profits to grow.
Even if each working department is placed in the most economical and efficient location, material handling costs still exist and must be included in the decision to set up a plant with this layout.
This layout does allow ease in automating all the machines in a department, however. For instance, an end forming department can have automatic loading and unloading systems doing the work and use one person to perform the material handling.
Workcell Manuafacturing. Workcell manufacturing was first introduced to U.S. industry in 1925. The cell manufacturing concept involves organizing machines from different departments into individual groups that can focus on a specific product or family of products.
Floor space can be maximized because material handling is reduced from large batches to individual units transferred from machine to machine within the cell. Work-in-process inventories can in turn be minimized because product flow is balanced.
Direct labor costs can also be reduced because products flow more quickly through the line and tooling changeovers are reduced.
Automating this type of arrangement allows one operator or technician to monitor a line. In most situations, a tube cutoff station supplies parts to an end forming operation and then moves the parts to a bending station. Autoloading the end former in the cell is similar to doing it in a function-oriented layout, except that transferring the tube to the next operation must be factored in.
If an employee has to manually unload a hopper that has been accumulating parts and then transfer those parts to the next automated machine, productivity is lost and the number of machines that operator can monitor is decreased.
Depending on the footprint of a machine, it may not be feasible to load the next operation directly from the previous one. Benders sometimes need a larger working area, and an autoloading system cannot be located right next to a loading system.
An autoloading system for each machine must be connected by a transfer system. This may be as easy as using a pick-and-place unit or robotic arm to load finished parts directly into the loading hopper or the next operation.
A disadvantage to the workcell layout is machine downtime. If a cutoff machine that is supplying parts to a production line needs repair, then the product flow stops if that machine is the only cutoff supplying the cell. Functional layout allows the job to be transferred to another cutoff machine in the department.
Cell manufacturing resembles just-in-time (JIT) manufacturing, in that JIT manufacturing attempts to eliminate storing products until they are needed, which lessens the time that products are not making money for the company.
When products arrive from a supplier and go directly into production, profits typically are realized immediately. The same is true in cell manufacturing—it is most profitable when products arrive from one station and move directly into the next operation.
Many types of automation are available. However, no automation system provides a one-size-fits-all arrangement. A method that excels in automating low-volume runs may not be beneficial to a high-volume product. Each manufacturer should look at several available options and their potential benefits and drawbacks before buying.
Low-volume Forming. Low-volume production runs require an autoloader that can be removed easily from a machine/process or quickly changed over to run another part.
In one arrangement, a hopper "walks" the tubes into the loading position by a stepping process, which keeps the tubes separated and prohibits the tubes from bunching during loading. A pneumatic cylinder with a side mandrel attachment loads the tube into the jaws of the end former, simulating manual loading. The cylinder then retracts to the load position during the forming operation. A pick-and-place mechanism grabs the tube and unloads it from the clamp jaws and places it in a hopper or transfers it to another machine or automated unit.
This type of autoloading is most beneficial if the autoloading unit can be detached easily and transferred to another machine.
In addition, this type of autoloading is applicable to high-volume tubes that have only one end formed and are produced on one or two dedicated machines. A large-capacity hopper or tube holder can allow one attendant to monitor three or more machines at the same time. One person also can monitor a manufacturing cell with transfer units from a cutoff machine to an autoloaded end former and then to a bender or whatever station is next.
High-volume Forming. A part produced at high volume may require a fully automated in-line transfer machine. This type of unit can combine several operations that require different machines.
The tubes are fed into a transfer unit from a hopper loading system. The tubes are then transferred from station to station. Once the end forming operations are completed, the tubes are unloaded by a pick-and-place unit and sent to the next station.
A unit can be designed to perform several different end forming operations, such as deburring, end forming, assembling, lockbeading, and roll/cut grooving. This form of automation can help to eliminate a lot of material handling time and labor.
Double End Forming. Another form of automation that can be used by a manufacturer that forms both ends of a tube, but not necessarily with the same end form designs, is a double end former.
This style of end former has forming heads on both ends—with one end adjustable for length—and can load the tubes in a magazine-type loader automatically. The tubes then are placed into a set of clamp jaws for end forming.
This style of machine is best for high-volume parts that have two formed ends, and it can be adjusted for various lengths of tubing. However, it is limited to end forms that require one operation on either end of the tube.
Dual Function Integration. A tube that requires end forming, loading of some sort of attachment, and a roll/cut groove normally requires two end forming machines and a groover.
A successful approach to automating this kind of operation has been to integrate both functions into one machine. This machine uses a single stationary clamp system for securing the tube. The end forming ram and the roll/cut grooving heads are mounted on a transfer station. This allows an operator to program many operating situations.
For instance, a lockbead can be produced by combining operations into one machine. The first operation creates the back bead. Without automation, the tube is taken to a roll/cut grooving machine and grooved. The tube then is taken to another machine, where a ferrule is attached.
An integrated machine allows the bead to be put on the tube before the machine transfers a roll/cut grooving operation to the tube. An end forming station then is transferred back onto the line to load the ferrule. This process is completed when the part is removed from the machine.
In addition to helping improve efficiency, combining two and possibly three operations into one machine can help to improve repeatability because tubes are clamped once during the cycle rather than being transferred to another machine and reclamped.
Automating a tube end forming machine, whether in a function-oriented layout or cell manufacturing process, is not a procedure to be taken lightly. It can aid in increasing productivity and efficiency, but a poorly designed system, combined with poor research and planning, can eliminate any gain and actually reduce productivity.
No one sells a one-size-fits-all system. Careful consideration must be given when evaluating various styles of end forming machines. Operations with tubes that require both ends to be formed and that are manually transferred from one end former to another may become more productive and efficient with an in-line transfer machine or a double end former.
In addition, a company should conduct a thorough review of its current production processes and the available options when it looks to automation to boost its efficiency and minimize material handling.
TPJ - The Tube & Pipe Journal® became the first magazine dedicated to serving the metal tube and pipe industry in 1990. Today, it remains the only North American publication devoted to this industry and it has become the most trusted source of information for tube and pipe professionals. Subscriptions are free to qualified tube and pipe professionals in North America.