Signicast aims for the future.
It's almost eerie. If you look around Signicast Corp.'s Hartford, Wisconsin, investment casting plant at 2 p.m., you'd think it's third shift and there's a skeleton crew on. There are very few people and very little product to be seen. Yet the plant, operating since June of 1993, is in full production and at 70% capacity.
"We bring a lot of customers through here," said Tim Mathers, technical sales manager, "and invariably, their reaction is 'Where is everybody?'"
The Hartford complex - a $12 million investment with 65,000 sq ft, and only the first of four planned modules to be completed - employs 110 people. It runs around the clock, however, and only 25-30 are on any one shift. It is a state-of-the-art facility - highly automated, computerized and nearly paperless. It uses continuous flow production and cellular manufacturing to process 1100 parts per hr, 24 hr a day, seven days a week.
The plant reflects Signicast's corporate philosophy, fast growth and confidence in the future. At its heart is the drive to be customer-oriented.
Signicast pours more than 100 alloys, including plain carbon, alloy, stainless and tool steels, ductile and gray iron, nickel, cobalt and copper-base metals for a variety of industries in the nonautomotive commercial investment casting market. "There are about 350 firms in that market," Mathers said. "We estimate we're about number two in size."
Founded in 1959, Signicast built its Milwaukee plant in 1972. That plant was expanded eight times over the next 18 years. Today, the operating facility also houses the corporate offices.
The firm continues to grow at an average of 20% a year, a rate Mathers attributes to a simple philosophy - "Deliver a quality product on time at a competitive price." The type of customers it serves are also important. No single customer constitutes more than 10% of the firm's business, ensuring that Signicast's prosperity isn't tied to the fortunes of a single industry. "We've worked very hard to diversify in the last 10 years," Mathers said. It shows in the variety of industries the company serves - from parts for motorcycles to high-tech health-care equipment.
Diversification has helped the firm redefine itself. "We are not a foundry," said Mathers. "We're not a job shop just pouring castings - we provide so many services, 'investment caster' doesn't do it. We are a custom components producer serving high-end customers.
"We are very growth-oriented - very hungry, very aggressive. But it's not just growth for its own sake. When we grow, we add capabilities and better serve our customers. When you grow, you innovate; when you stop, you become stagnant and die."
Adding capacity is the investment caster's main priority. "No matter how much customer requirements swell," Mathers explained, "we want to be able to respond. Even in times when we didn't have the capacity, we figured out how to get it. You can't tell a customer today you don't need the work, then tomorrow go knocking on their doors looking for more. That's something sand casters have traditionally done, and done themselves a disservice in the process."
A lack of capacity in sand foundries during the last couple of years is only one reason more and more of Signicast's new business consists of parts that were formerly sand cast. According to Robert Schuemann, vice president-sales and administration, the traditionally far more expensive investment method "has remained much more steady in cost than sand casting over the last several years, so that gap between the processes is closing. So if the price is comparable, and lead time is an issue, we're going to get the part. Most investment casters don't have the 30-week lead times sand casters do."
Amplified demands for near net shape castings are also spurring sand casting defections. "Investment castings allow customers to use their $250,000 machining centers to do what they're intended for," Schuemann said, "which is the detail work. They don't make money by how much scrap metal they generate from machining non-net shape parts."
Upon completing the last expansion in 1990, Signicast ran out of room at Milwaukee and had to build a new plant. Officials saw this as an opportunity, as Schuemann attests: "For the first time we had a clean sheet of paper to build the plant where and how we wanted. That's when we decided we didn't want a 'me too' type of plant."
Signicast took several steps to ensure an original shop design. First, customers were surveyed to find out what they wanted from an investment casting company. The response that came back was decreased lead time and decreased cost. Next, they searched for a model, looking outside the investment casting industry.
"We've learned an awful lot from our customers," Schuemann said. "That's what sets us apart from a certain inbreeding that can happen in an industry. We're not so set in our ways that we can't learn new things."
The new plant had to cut queue and lead times while maintaining costs. A model was found in a chemical plant. "There was no one thing they did that we emulated, but we wanted a process industry model to determine the quickest way to move product through the plant," Schuemann explained.
An overall design for a manufacturing facility comprised of four separate modules was developed [ILLUSTRATION FOR FIGURE 1 OMITTED], and once the Hartford site had been selected, ground was broken for the first module in June 1992. Eleven months later, the first production castings were coming from the new plant.
Continuous Flow Production
To get its investment castings from order to shipment as fast as possible, Signicast turned to continuous flow manufacturing. It was implemented via computerization, automation and cellular manufacturing. The plant is controlled by a $1 million software package, consisting of Signicast Manufacturing Automated System/Hartford (SMASH), which directs and tracks all manufacturing operations, and statistical analysis software (SAS). The logic for the system was written in-house at Signicast, before being translated into computer language by an outside firm. It includes 21 Allen Bradley PLCs that track castings by part and lot numbers, communicates to SMASH, and controls the robotics.
The production sequence begins when the wax injection press operator signals the SMASH software that one job is complete and a new die is needed at the workstation. An aluminum die, preselected by production control software, is delivered to the wax injection cell via an automatic storage and retrieval system (ASRS) made by Munck Automation [ILLUSTRATION FOR FIGURE 2 OMITTED]. The ASRS also delivers the proper wax sprue blanks that will eventually form the trees.
At the station, the operator loads the die into the automatic wax injection press. The units, designed by Signicast and built by Mueller Phillips, use Signicast's patented semisolid wax pumping and injection system, which was first instituted at the Milwaukee facility.
"We store, pump and inject wax in a semisolid state, rather than liquid," Mathers explained. Injecting the wax at the semisolid 118F (47C), rather than 135F (57C), reduces dimensional changes the cooling wax patterns can undergo. The wax is melted at a central station and pumped to all the presses, eliminating the reloading downtime of traditional methods.
The presses typically produce 60-100 patterns per hr, and their automatic operation frees the operator to assemble trees from the completed patterns [ILLUSTRATION FOR FIGURE 3 OMITTED]. Once the trees have been completed, the operator returns them to the ASRS, which will store them until the dip cell is ready to take them. Then, it delivers the trees the same way it delivers dies to the injection cell.
In the dip department, a single operator is in charge of the three Fanuc GMF robots that dip the patterns, coat them with the zircon sand and stucco, and place them in the shell drying system [ILLUSTRATION FOR FIGURE 4 OMITTED]. The shells get seven dip coats, and each coat would normally take 8-16 hr to dry. However, Signicast's system uses various air velocities and humidities in a controlled environment programmed by part number to dry batches of 40 hangers. Each ceramic coat is dried in 3 hr, and the entire shell can be dried in 18-24 hr.
"We can build the shell in a day, rather than the typical week to week and a half. That takes out a lot of lead time," Mathers said. With the robots performing the dip operation, the operator's job mainly involves SPC checks for viscosity and pH levels, as well as replenishing materials.
From the dip cells, the completed and dried molds go automatically to the dewax cell, where they enter the autoclave, which was designed by Signicast. The dewax programs are part-dependent, but they usually use a temperature of 350F (176C) and pressure of 110 psi, for a cycle of 18 min. The melted wax is reclaimed - dewatered, filtered and tested before use in making sprues. Next, the molds go to the burnout oven for a minimum of 4 hr at 1800F (982C).
During all these operations, Signicast's software is keeping track of the progress and needs of every part going through the plant. "When you have a part going from the burnout furnace to the melt," Mathers said, "the PLCs know exactly what molds are in what lanes going through the burnout. When the operator takes a mold out of the furnace and puts it in the sand for pouring, the system knows what part it is."
It also knows the pouring instructions for each part, and those instructions - pour weight, pour speed, etc. - are displayed on a marquee in the melt cell. Thus, each part is poured correctly and consistently. The system operates the same throughout the plant for every part, with marquees in each department showing the status and instructions for parts at the various stations. Every workstation incorporates a PC, which conveys part data and lets the worker enter his own [ILLUSTRATION FOR FIGURE 5 OMITTED].
The melt cell incorporates two Inductotherm induction furnaces, and the ideal metal chemistries are maintained and given to the furnace operator via the SMASH data base. A spectrometer is used on every heat for SPC, and metal chemistries are held closer than customers' specifications. Mathers explained melt cell operations: "We have a three-man melt crew - one charges and operates the furnace and does all the necessary chemistry and testing, another operates the ladle, and a third readies the molds for pouring.
"When a particular heat is done, however, those two guys go and run the autoclave, the burnout furnace, the water jet blast or the cutoff. All they do is basically stage the conveyors, so they're not really performing the operations and don't need to be at any station all the time. Those three guys run an entire third of the plant!"
In the water jet blast, the next step in the operation, the poured molds are suspended from a conveyor and enter an enclosed unit one at a time. Once inside, the mold is transferred to a spinner-hanger and robotically manipulated nozzles rotate around it, blasting it with 8500 psi of water to break away the ceramic shell. Again, the unit is controlled to work specifically on each part number so that it adjusts to the particular needs of each. The cleaned tree is then air dried before heading to cutoff.
After cutoff, the individual parts are loaded in tote pans onto an overhead conveyor for transport to the finishing cell on the other side of the plant. There, the gates are ground off and the parts enter another ASRS until delivered to the finishing operator. They are then automatically delivered to a Goff sandblast unit for blasting. For those parts that require straightening, there is an in-line straightening unit.
Signicast has recently installed an in-line heat-treating cell. "If we're making a part in four days," Mathers said, "the four to five days it takes to send out and get back parts from a heat treater kind of defeat the purpose. Now, we can treat it as just another plant process that takes about half a day." The department consists of a vacuum furnace for vacuum annealing, a combination atmosphere furnace/quench tank, a temper furnace and a parts washer, all built by Holcroft.
"When we tell people we can deliver a heat treated casting in two weeks," Mathers laughs, "the most popular response is 'yeah, right!'"
Without bottlenecks, backtracking, or much inventory, Signicast has cut lead time to four or five days. Throughout the plant, the system of colored lights paces the work to the workers, while in each department, an overall "Customer Satisfaction Index" board also uses colored lights to give a general picture of the department's pacing [ILLUSTRATION FOR FIGURE 6 OMITTED]. Scrap, which averages about 3%, and departmental and personal productivity are charted and posted throughout the facility.
Lead Time Reduction
The result: the Hartford plant offers lead times of less than half that for typical investment casters, while maintaining competitive prices. For parts that require no heat treating, it isn't uncommon for orders to be turned around in week. Mathers recounted the first time Signicast management truly realized "the power" of the new plant:
"One customer picks up its orders on a milkrun basis - every Tuesday morning they send a truck and we have their parts waiting. One Friday evening not long after start-up, Terry Lutz (Signicast president) looked at the schedule and said, 'Wait a minute, this can't be right. We're never going to make it.' The parts were just being injected, and they had to be ready on Tuesday morning. But they were as-cast, and we turn them around that fast on a regular basis."
Provided they have at least two weeks notice, Mathers said, the Hartford plant delivers 100% on-time to the customers' requested dates, not to Signicast's acknowledgment dates. In designing the plant, the type of castings made were as important to the workflow as methods of making and transporting them.
For a part to qualify for production at Hartford, it should be ordered in a blanket and released in a lot size at least once a month. According to Mathers, "What optimizes the plant is if something is released every week - that's the way the plant's set up. But we have the flexibility to work with a customer's special requests."
The new plant is set up to house a certain amount of dies, with 253 there now. That number is directly based on the flow of parts through the plant at any given time, which means the dies of customers who don't order frequently enough are moved to the Milwaukee plant. Scheduling is set up so that most of the queue time (the time the part waits its turn for injection) is eliminated.
The site is purposely restricted in its product mix. Unlike Milwaukee, Hartford has only fully automatic wax injection, which limits the complexity and size (5-7 lb maximum) of the parts to be cast. All the more complex jobs - parts up to 200 lb, or those requiring soluble or ceramic cores or special cutoff - are still run at Milwaukee. Those customers who don't expect delivery on a just-in-time basis, and order 4-5 times a year (still the majority, Mathers says), will still have their parts cast at the older facility.
Also, only about 30 different alloys are poured at the new plant. "With the continuous flow, you can't pour 170 different alloys and 4200 different parts, like we do in Milwaukee," Mathers said. "We want to narrow down the options for the new plant and focus on lead time and costs."
Personnel and Service
To make the fast, highly automated system work, Schuemann said, "you must balance the workflow to the labor. In eliminating so much of the drudgery and materials handling, you don't need a lot of people. But those you do have must work smart - it can be pretty demanding out here. That's why cross training is so important.
"Everybody has to work as a team because things get done a lot quicker than they used to, and problems must be solved immediately."
After an intensive training period, entry level employees at Hartford know a minimum of two jobs when they begin, and are expected to quickly learn more. Workers must be PC and PLC literate, or be willing to learn. The pay scale is based on both performance and knowledge. "The more jobs you know and the better you do them, the better your pay," Schuemann said. "You control your own destiny."
During the 12-hr shifts, nobody works more than six hours at the same operation, and employees' time is tracked on a credit card scanner system. When a worker moves to a workstation, he inserts his card and the computer automatically records his time there and the number of pieces processed through the station. The computerized pacing system lets him know exactly where he should be as work flows through the plant.
With the Milwaukee plant still in full operation at three shifts, Signicast has the ability to provide diverse services to its growing customer base. These extend to engineering support, including CAD, concurrent engineering and a variety of rapid prototyping processes. Another service is CAD data transfer, which enables Signicast to build hard wax injection tools from customers' CAD files - in some cases in as few as three days.
"We can quickly build a single-cavity manual die for a prototype," Mathers said. "It's a route many of our customers are taking for simpler parts, rather than rapid prototyping, which can take up to 12 weeks start to finish. It's less costly for simpler parts and in many cases we can build a die in a week."
With its CNC machining center at the Milwaukee plant and lighter machining apparatus in Hartford, Signicast has the capability to provide a completely finished product. While 30% of their total product requires machining, 90% of the parts it furnishes complete are done in-house. The firm will also paint and assemble, going so far as boxing and assembling kits that go directly to the end-user without inspection.
"Some of our bigger customers," Mathers said, "don't want to inspect parts. That's your responsibility as a supplier. After a qualification process, they give you the OK to just ship the product right in to the line."
Going From Here
Starting up the new plant was remarkably smooth. The debugging period was brief, and bugs found were minor - much to the relief of company officials. Since start-up, Hartford has filled up quickly. At full capacity, which it is expected to reach soon, it will generate $30 million a year in casting sales. "Customer response has been overwhelming," Mathers said. "They see short lead time and time to market, plus the time to make engineering changes. And it's gone from the stage where we're talking about it to where we're doing it."
Eventually, all four modules will utilize the continuous flow concept, each using slightly different processes to cast slightly different types of parts. The total complex will house the corporate offices, and operate as a stand-alone facility, with comprehensive in-house machining capabilities. Signicast is already planning construction of the second module, to be started next spring. This module will also focus on just-in-time delivery, though with a more diverse product mix, tentatively allowing larger parts to be cast. It will employ another 110 people, and is expected to add another $25-30 million in sales.
"Some people think we're going ahead with the second module too soon," Schuemann said. "But if a recession is coming, we need to keep building through it, so we have capacity when we come out of it. Somebody in the organization has to be willing to say, 'if we build it, there will be business when we're done.'
"That's what we did with the first module, and we ended up growing at a time when the rest of the industry wasn't. We're confident that we've really just scratched the surface."
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|Title Annotation:||Signicast Corp.'s manufacturing plant|
|Author:||Philbin, Matthew L.|
|Date:||Oct 1, 1995|
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