Consolidating your cleaning room: by implementing new designs and practices, two steel casters anticipate improvement in their cleaning and finishing operations.

As domestic steel casting firms still recover from the economic slide of 2001-03, production methods must be at optimal levels to handle increased orders. This is necessary to increase profit and supplement continuous improvement efforts against growing competition.

Two firms, The Falk Corp., Milwaukee, and Harrison Steel Casting Co., Attica, Ind., saw a particular need for improvement in their cleaning and finishing departments. Although each firm faced different conflicts, both saw the need to redesign its practices in these departments to optimize their production.

With the new operating procedures, both firms anticipate a significant improvement in their finishing department, leading to a more efficient operation.

Falk: Redesigning

Last summer, The Falk Corp., which casts steel components for power transmission applications, began implementing a large consolidation project at its casting plant in Milwaukee to minimize the material travel, cut down on material handling and maximize the effectiveness of the queuing systems. The firm had both a large and small cleaning room at its facility, and the project called for a redesigned layout and a new location for the small room, which would free significant shop floor space for other operations.

Before the improvements, one of the main problems that Falk dealt with was the location of this smaller room--a corner of the plant 500 ft. (152.4 m) from the larger cleaning room. Many of the parts produced (4,000 lbs. [1,814 kg]) were originally heat treated and annealed in close proximity to the small room, but with the phasing out of old heat treatment ovens, many of the parts were being moved to and from the heat treat facilities--1,000 ft. (304.8 m) away at the far end of the larger cleaning room.

Several other major problems included the inefficient use of floor space and disruptive layout of equipment and staging areas. The equipment in the old cleaning room was not laid out for optimal use of space or flow of material, significantly affecting process time, material handling and work in process inventory.

As a result, Falk implemented a $1.2 million project to optimize its small cleaning room in its new location.

Establishing a Plan

Falk established several steps for the consolidation process, beginning with determining the location and available workspace of a new cleaning area and comparing it with the old area. Another early step was to gather information from the old small cleaning room in order to optimize the layout of the new area. The firm gathered data throughout 2004 on nine of the highest production castings in the previous small cleaning room and analyzed it to determine their requirements (Fig. 1). Falk wanted to determine the number of castings being processed in the old room, how often each casting was being produced and the average travel distance and time castings spent in the cleaning operations.

Two casting types in particular, hubs and A-gears, made up 65% of the work processed in the small room, so the layout of the new room would be tailored to the requirements of those castings. The new room operations were planned to be the same as the old room but with increased capacity to accommodate slightly larger castings (4,000-6,000 lbs. [1,814-2,722 kg]) and a higher volume of castings. This was done in part by installing cranes with larger capacities and considering larger queuing areas in the design.

As a means to phase out older equipment and help facilitate larger castings, Falk purchased a larger tumble blast unit and a door blast unit, both with dust collection systems. In addition to the two blast machines, the new room also includes equipment pulled from the old room, such as a gas cutting machine with turntable, hand gas-cutting tables and equipment and an arc-air booth with dedicated dust collection system. The cleaning room is completed with a warming oven, two welding booths, two grinding stations and an inspection station.

Foreseeing Improvement

The layout of the new room revealed a substantial improvement over the previous location. Figure 2 shows one example of the travel distance differences between a casting in production in the previous small cleaning room and the same casting in the new small cleaning room. The old material flow traveled about five times as far as the new flow, which was the case for most of the nine castings produced in the smaller cleaning room. Thus, a part could have traveled as much as 2,000 ft. (609.6 m) by the time production was complete. In the new design, the part travels less than 600 ft. (182.9 m) before completion.

Another significant improvement is that the number of material handling changeover points (transfer car, crane, or other method of transport) in transport has been reduced from eight to five. This is important because changeover points are not a value-added event, and they consume time and energy of both the operators involved and the equipment used in the process.

It was determined that in the new small cleaning room, the finishing operations on hubs and A-gears alone will save 57 miles (91.7 km) of travel each year. When adding all of the parts produced in this cleaning room, the total travel distance saved each year will be more than 100 miles (160.9). This also is due to the fact that some of the smaller production volume castings traveled an even more complex route before the improvements. Distances between reworking operations also were reduced in the project. Material handling changeover points were greatly reduced; however, it is difficult to predict the extent of its impact because it is not yet known how the parts will travel in groups. But if each casting is transferred by crane and transfer car separately, the transfer point count decreases from 3,864 points to 2,415.

By moving the operations toward the larger cleaning room, not only has Falk been able to close the distance between similar cleaning room operations, but also redesign the material flow patterns for optimal efficiency (Table 1).

The purchase and installation of the new blast machines cut blasting operation times in half. This is largely due to more efficient and powerful blast equipment and simplified access to and from these operations, which will allow for minimal material handling and time savings for each casting. Further, this also will allow for extra machine time to process more castings.

Falk plans to increase production through more readily available workers and equipment; closer proximity of similar processes allowing better control and supervision of operations, equipment and laborers; and better flow through all stages of production and processing. In addition, improved lighting and safety equipment has been installed in the new cleaning room, and several improvements in overhead cranes and other equipment were added to the overall project.

Falk will continue with the consolidation project by relocating other machining operations and equipment to the location freed up by the move of the old cleaning room.

The new cleaning room is now fully operational, and entirely evacuated from the old location.

Harrison: Grinding Ahead

While Falk found success with a new layout, Harrison Steel Casting sought to eliminate wasteful tactics in its production of construction and agriculture castings with grinding wheels. After enduring a lack of production at the beginning of the decade, Harrison's business picked up recently (the firm sold more than 32,000 tons worth of castings in 2005, which was a 12,000-ton increase from 2001 and expects even higher numbers in 2006). This gain called for the training of additional personnel especially in the finishing department at the grinding operations.

With its expanded production, Harrison noticed that numerous piles of grinding wheels began to accrue adjacent to the grinding stations. These wheels, measuring 8 x 1 x 0.625 in. (20.32 x 2.54 x 1.59 cm), were in various stages of their life expectancy, and questions arose on how economical the grinding operations were as well as how large piles affected worker safety. As a result, the firm investigated the reasons for the partially worn wheels and how to improve the overall grinding capabilities.

Finding the Dilemma

Harrison has two types of grinding machines, a large high-frequency electric grinder, which uses 8-in. (20.32-cm) wheels, and a small high-frequency grinder, which uses 4-in. (10.16 cm) wheels. Once an 8-in. (20.32-cm)

wheel has been worn down to a diameter of 4-in. (10.16 cm), it can be placed on a small grinder and still function. This is the main source of all 4-in. (10.16 cm) grinding wheels for the small grinders.

There are also two stages of hand grinding performed at Harrison: chip grinding (for the head and riser contact areas and the seams along the parting lines) and finish grinding (for working on welded castings and finalizing any work begun by chip grinding). Chip grinding requires a machine with the largest wheel manageable in order to remove a large amount of material in the shortest amount of time. This operation uses the large machines mostly, but sometimes the small machines are used, also.

The finish grinding utilizes the large high-frequency electric grinders and the small high-frequency grinders in near equal amounts. But finish grinding requires a smoother surface texture than chip grinding and rarely needs the full cutting abilities of a new 8-in. (20.32-cm) wheel because this grinding is sometimes impossible to do with a full-size 8-in. (20.32-cm) wheel.

Because the finish grinders' work is more detailed than chipping grinders', they have to work in tighter areas. Harrison found that some of the finish grinders would go to the chip grinders and collect the cast-off wheels for the purpose of having a wider selection of wheel sizes available for different scenarios. These finish grinders relied heavily upon the chipping grinders as a source of pre-ground wheels for use on the small machines. Unfortunately, they would collect many more wheels than they could use, which lead to the chipping grinders mistakenly believing that the majority of the partially used wheels were being completely used. These practices accumulated piles of used wheels in some of the finish grinders' work areas, so Harrison sought a controlled exchange system to manage the consumables in the grinding process.

Implementing Change

In order to develop a solution, Harrison took a trial-and-error approach based on past experiences of the grinding operators and sought to eliminate spoilage, waste and clutter without interrupting or hindering production.

The first decision made was to eliminate the palettes of grinding wheels on the floor among the castings. Although providing a cabinet, or some other type of designated area, may have prevented damage to unused grinding wheels, it still would have allowed uncontrolled access to the grinding wheels by the individual hand grinders.

Unlimited access to the consumables was considered to be one of the primary factors contributing to wasteful practices. The alternative to storing grinding wheels on the production floor was establishing a system to deliver new wheels to and remove worn ones from the hand grinders at their work stations twice per week and recording an inventory of the new wheels at the end of every week. Each grinder would be allowed to maintain a personal stock of 8 x 1 x 0.625-in. (20.32 x 2.54 x 1.59-cm) wheels in various stages of use, with a maximum of 25 wheels for a finish grinder and 40 for a chipping grinder.

Next, Harrison examined the lifespan of the wheels. The tested wheels can be used safely until only 2 in. (5.08 cm) of the original diameter remains. But when an 8 in. diameter grinding wheel has been worn down to a diameter of 5 in. (12.7 cm), it's no longer useful. This is because the effective cutting speed has dropped so low, the force required to continue removing material at a sufficient rate is too difficult to maintain and the body of a large grinder will collide with the castings more frequently as the wheel size decreases. The wheel also would be too large for a small grinder and would damage the machine.

In the grinding operations, the full life cycle of each wheel varies, and the number of wheels worn from 8 in. (20.32 cm) diameter to 5 in. (12.7 cm) diameter during the chipping process far exceeds the number of 4 in. (10.16 cm) wheels in the chipping and finishing process combined. It was decided that a grinding operator would be allowed to exchange any wheel with a diameter of 5 in. (12.7 cm) or less, for a new one.

To accurately ascertain whether the wheels are an adequate size for the machines, Harrison established a measurement system in which a sweep gauge device is used to determine three specific measurements while the wheel is mounted on the machine (Fig. 3). The gauge is used by passing it over the wheel in a direction perpendicular to the centerline of the machine. A copy of the sweep gauge was attached by a chain to a grinding stand at each work station, and a copy is provided to the wheel delivery person to use during delivery rounds.

Rotating Ahead

When the wheel exchange system was implemented last April, Harrison found a preliminary decrease in wheel usage of 33%. By controlling the disposal of used grinding wheels, as well as the distribution of new wheels, there are no longer loose wheels in the aisles nor are there piles of used wheels in the hand grinding work areas, so all of the workers in the cleaning room can operate in an inherently safer environment.

This article was adapted from two papers presented at the Steel Founders' Society of America 2005 Technical & Operating Conference, November 2005, Chicago.

About the Authors

Brad Bishop is a student in the Industrial & Manufacturing Systems Engineering Dept. of the College of Engineering at Iowa State Univ., Ames, Iowa, and was an engineering intern for the Falk Corp., Milwaukee, during the summer of 2005. Don Hawn is a process technician, and Sony Mascreen is a process engineer at Harrison Steel Casting Co., Attica, Ind.

For More Information

"Getting More from Your Cleaning Room," D. Spinner, F. Peters and K. O'Shaughnessy, MODERN CASTING, January 2005, p. 33-37.

"Opening Up to Robotic Change," R. Anaparti, MODERN CASTING, January 2004, p. 40-42.

Table 1. A Flow Comparison Between Falk's Old Small Cleaning Room and
New Small Room.

Old Flow                   Travel    New Flow                   Travel
                          Distance                             Distance
                           (ft.)                                (ft.)

From Transfer Car at                 From Transfer Car at
80-ft. bay                   --      80-ft. Bay                   --
Crane Pickup to Heat                 Crane Pickup to Heat
Treat                        --      Treat                        --
Crane Pickup to Crane                Crane Pickup to
Transfer Point              150      Blast Queue                  --
Crane Pickup to Blast                Crane Pickup to Blast        20
Queue                       275
Crane Pickup to Blast        25      Crane Pickup to Center
                                     Transfer Car                100
Transfer to 50-ft. Bay       25      Transfer Car to Saw
                                     Queue                        60
Crane Pickup to West                 Crane Pickup to
End 50-ft. Onto Skid         75      Saw Queue                    25
Forklift to Saw Queue       300      Crane Pickup to Saw          50
Forklift to                          Crane Pickup to Skid,
Saw Setup                    25      Post Cut, Inspect            25
Crane Pickup to Saw          15      Forklift to Destination      --
Crane Pickup to Skid,
Post Cut, Inspect            15
Forklift to Destination      --
Total                       905                                  280
Average Annual usage        483      Average Annual Usage        483
Travel Distance (miles)      82.79   Travel Distance (miles)      25.61
Travel Distance (miles)
Saved Per Year               57.17

Fig. 1. Falk recorded the nine largest volumes of castings processed in
the small cleaning room operations in 2004. Hubs and A-gears were found
to represent 65% of total processing work.

Previous Small Cleaning Room Castings--3,260 Pieces

Hubs               1,375
A Gears              737
Misc.                452
Gears                353
Y Gears              298
Flanged Sleeves      180
Clutch Rims           96
Bearing Cages         70
Carriers              59

Note: Table made from bar graph.