A steel casket is more than just a large metal box. The 2009 Assembly Plant of the Year uses many different manual and automated assembly processes to create a dignified product with an elegant look.
A steel casket is more than just a large metal box. Many different manual and automated assembly processes are used to create a dignified product with an elegant look.
“The most challenging aspect of building caskets is knowing that the product will be used at one of the most difficult times in the life of a family,” says Mary Jo Cartwright, director of operations at Batesville Casket Co.’s Manchester, TN, steel casket plant. Her facility assembles more than 1,000 steel caskets every day.
“Our team [always wants] to be sure that we provide a high quality casket to honor a loved one at that time,” explains Cartwright. “We push hard to have repeatable, reliable processes which yield diamond standard quality. We all can relate to choosing the ‘right’ casket as a consumer.”
All casket tops and bottoms are stamped from a single sheet of carbon steel, which adds to each product’s strength and rigidity. Once the top is formed, steel flange strips are installed inside the entire perimeter of the rim. This reinforces the closing flange and provides a means for installing materials to the interior of the top.
“We recently added equipment to install flanges in the shell,” says Cartwright. “This automation eliminated a manual welding process, which [presented] concerns from an ergonomic standpoint.”
After all metal and plastic components are stamped and molded in different corners of the 450,000-square-foot plant, the process of assembling a casket begins. The first step is metal fabrication.
Batesville Manchester, the 2009 Assembly Plant of the Year, prides itself on seamless welding. That joining process ensures a strong water- and element-resistant container.
Five basic metal components are needed to assemble a casket shell: a bottom panel, two side panels and two end panels. Shells are manually welded, while lids are welded separately on an automated line. A continuous seam weld secures the casket bottom to ensure its structural integrity. Casket bottoms are also stamped with several reinforcing grooves, which add strength and rigidity.
Assemblers at Batesville Manchester build caskets with both square corners and round corners. For square-cornered products, a continuous MIG weld is used to join parts. Later in the assembly process, decorative corner hardware is attached to cover up the seam created by the miter joints.
Round-cornered caskets are more elegant, but they require a few more production steps. End panels are pressed with rounded corners. Side panels are welded to the end panels about 4 inches from the corner using joggle joints. Round-cornered caskets typically do not contain any decorative hardware, so the welded joints must be manually sanded to a point where the seam is not visible.
On some caskets, an anodized zinc rod is attached to the bottom of the shell to help prevent corrosion. After the rod is placed in an indented trough, it’s held in place with metal brackets that are spotwelded. The cathodic protection system inhibits the formation of rust on the outer surface of a casket. The zinc bar acts as an anode, while the metal casket itself acts as a cathode.
Batesville Manchester prides itself on the smooth finish and elegant appearance of its products. As a result, the plant uses an automotive-quality paint line as part of its five-step exterior finish process. Lids and shells are matched up and painted at the same time to ensure consistency. To boost volume, they hang vertically on an overhead conveyor as they receive a primer coat, a color coat and a clear top coat from four robots.
Operators constantly look for defects and flaws as the lids and shells exit the paint shop. Some caskets are pulled off the conveyor to receive a shaded finish. For instance, a blue casket may receive a silver shade to give it a more distinguished look. Some caskets receive two different shades of the same color. “This customized process is done manually, after a casket exits the robotic paint line, because it is a very unique and difficult operation,” says Cartwright.
The final assembly line at Batesville Manchester is divided into two main sections, each supported by subassembly lines. A decade ago, the facility converted from a pulsed line to a continuous, moving line. Today, caskets flow past assemblers on a power-and-free conveyor.
The first half of the L-shaped production line is devoted to hardware assembly, which consists of approximately 10 workstations. Operators use pneumatic screwdriving equipment to attach handles, stationary bars, swing arms and other components on subassembly lines. The hardware provides a means of carrying a casket, but also adds to the distinctive look of each product.
The typical casket contains about 24 exterior hardware components. Once the parts are assembled, they are placed in the appropriate casket and sent down the line. Hardware is installed with pneumatic fastening equipment using stainless steel bolts attached directly to the casket sides. Gasketed nuts secure the holes made in the side panels, which enhances the casket’s resistance to moisture and other elements.
Plastic corners and other decorative accents are attached with adhesive tape. Rubber gaskets are also attached to caskets with double-sided tape. The one-piece gaskets are manufactured at an on-site facility.
A leak-proof plastic liner is inserted into the bottom of every casket. The puncture-resistant tray is manufactured from recycled material. A vacuum test is also conducted to ensure the integrity of each casket.
Casket tops travel via overhead conveyor to the end of the hardware assembly line, where they are attached with nutrunners to the appropriate shell. The closing mechanism is comprised of a wedge bar, pull-down studs and pressure-equalizing hinges, which ensure an element-resistant close.
At the last workstation on the hardware line, a metal bed frame is inserted in the bottom of each casket. It is attached with fasteners to the vertical head and foot panels.
The second part of the final assembly process at Batesville Manchester is the interior trim line. All caskets receive a fabric lining that can be either crepe or velvet. In addition, the material can be tufted, shirred or tailored, allowing for a wide range of customer tastes.
There are seven workstations on the interior line. “We use staples, adhesive tape, adhesive and thread, in addition to staple guns and sewing machines,” says Rick Ring, quality manager.
“Material arrives [on rolls] in 63-inch widths,” explains Ring. “We slit to 12 different widths. We laminate the material with heat pressure and gear pattern for three unique patterns.” Parts and components for the interior are sewn on subassembly lines.
“The dish assembly takes pieces through the lamination process and we attach corrugated material,” Ring points out. “We form the dish assembly (the part that is inserted into the top of each casket) and staple it using an inserted panel in the center. This inserted panel can be customized.”
Even though it’s a lean facility, automation has played an important role at Batesville Manchester for many years. “We continually investigate different methods of manufacturing our products,” says Todd Howell, engineering manager.
“A recent example of integrating mechanical technology can be found in our interior department on machines we refer to as the re-roller and the automatic parts staple,” explains Howell. “As material exits the shirr machines, the re-roller, a custom machine consisting of a DC motor-powered rotating shaft, rolls a continuous piece of material. This roll is then transported to the head dish construction operation.
“The dish construction operation is now completed by the automatic parts staple machine,” adds Howell. “This machine scores cardboard components, attaches the rolled material through the use of an adhesive, cuts the material to the correct length and stacks the finished dish component. This automated process is a revolutionary change to the interior department and has paved the way for further improvements.”
The majority of 18- and 20-gauge steel caskets built at Batesville Manchester are personalized and built to order. In fact, more than 850 different models are produced on the same assembly line every day. The highest volume of any model is only 47 per day. Caskets are equipped with an endless variety of options and features, such as different exterior colors, interior fabric styles and colors, and different exterior hardware, such as decorative corner accents.
That constant demand for personalization requires Batesville Manchester to operate an extremely flexible manufacturing process using a mix of make-to-stock and make-to-order items. To meet that demand, the plant relies on an automated production scheduling system.
Every workstation on the assembly line is equipped with touchscreen computers. Operators can easily access critical plant floor data and paperless work instructions. Work orders are created and displayed for both the first and second shifts
Every customer order automatically triggers inventory replenishment, which in-turn, triggers production. That allows orders to be filled accurately and delivered quickly. By harnessing computer technology, Batesville Manchester is able to achieve on-time delivery more than 99 percent of the time and maintain a competitive edge in the marketplace.
How a Casket Is Assembled
October 9, 2009