Achieving Integrated Manufacturing
Achieving integration in the production of ceramic goods, especially sanitaryware, is coveted because of the numerous advantages it confers, including flexibility, reliability and optimization of the cost/benefit ratio. However, these advantages involve many interconnected factors. Integration is a "whole" in the sense that it is global, coordinating all the activities that take place at various levels of the production process, its component stages (each of which represent a certain segment of the production line) and machine operation (i.e., the activities carried out by the machines in that segment). The diagram shown in Figure 1 illustrates these factors and their connective dynamics.
The cycle that makes integration efficient can generally be examined starting from a company's marketing programs. These programs define products as a function of a specific market strategy-products that, on account of their design, type and the area in which they are to be sold, will require defined quantity and cost programs.
Marketing programs are also linked to the choice of production formula, which obviously depends on the type of material used for the molds. The complexity of the piece and the required output rate will influence the choice of casting system and the relative machine. Process integration thus reappears in individual segments of the production line and within the segment in the choice of machinery.
However, while process integration depends on upstream entrepreneurial decisions, it is achieved from a practical industrial viewpoint that starts with the basic question: Which casting system should I use?
100 x 1 is Not the Same as 10 x 10In most cases, the barriers to implementing the appropriate casting system are created upstream. They stem from company strategy-from the clash between production needs, which, ideally, would aim to provide a lot of pieces with as few variants as possible, and commercial strategies, which necessitate great variety and innovative design in limited quantities by using production methods that are as flexible as possible.
In short, 100 x 1, or, at the most, 50 x 2, compared to 10 x 10 (or anything less, such as 5 x 20) would mean almost artisan-like production.
On the technological front, such a scenario would involve the use of various casting systems, mostly of the high-pressure sort. On the one hand are plaster molds, which don't last long but are replaced frequently since they are used for relatively small lots of varied, complex items. On the other hand are long-lasting resin molds with multiple casting processes that supply downstream departments with a high number of low-complexity pieces with few variations in design.
However, an intermediate area also exists in which it is convenient to use systems that can produce varied and complex pieces in considerable quantities, the maximums and minimums of which vary according to demand and the need to provide a "just in time" response. Achieving this goal requires equipment and methods that allow the manufacturer to produce variable-complexity pieces in considerable quantities. It also necessitates faster cycles, the elimination of difficulties associated with mold configuration (number of parts, piece complexity, etc.), and a level of automation close to that used in mass production.
In this context, it is difficult to identify quantities that correspond to the practical realities of numerous producers, both large and small. However, all are equally interested in producing new, well-made, well-designed, unique, high-quality items in quantities and at output rates that are both reasonable and profitable.
But how complicated should such pieces be? And in what quantities must the pieces be produced?
The problem is that no formula or number exists that can be shared by all producers. What is "quite complex" for a producer in Asia might not be complex enough for his European counterpart, while the quantity envisaged by an American enterprise as "plenty" may well be too much for those operating in markets in developing countries.
If the Problem is Upstream, the Solution is DownstreamThis problem won't be solved by establishing (debatable) fixed quotas for cycle times, the number of pieces per day, the number of parts per mold, and so on. What is needed are machines that can comply through problem-free, efficient, reliable performance with changeable, variable production cycles-machines that are changeable in terms of complexity and variable in terms of quantity.
Recently, a solution to this problem has been developed in the form of a single-mold machine* that offers high-pressure casting with resin molds and draws on the technology used in similar multi-mold modules.** The new system essentially combines the reliability of large-scale production (with the resin molds providing versatility, precision and duration) with a flexibility that allows product type and output rates to be varied quickly.
Reliability stems from a number of machine-mold integration factors. For instance, proportional hydraulics are used for mold closure to minimize tension and mold deformation, thereby ensuring longer-lasting performance and maximum precision, even after thousands of castings. Additionally, the rim is cast with the mold in a vertical position, which is the most suitable position for natural, homogeneous filling and provides better piece quality. The piece also rests on its base, and the side parts detach symmetrically with forced de-molding, thus ensuring a deformation-free release. And the weight of the machine does not rest on the mold but is spread over the various parts of the structure, which prevents any unnecessary stress from being placed on the mold and helps ensure a longer mold life.
The system also uses customized high-pressure casting resins. This manufacturer-specific synergy gives every producer a formula that is in keeping with its design and process strategies, thus allowing companies to manufacture a wide range of product types.
Proper materials/molds/machine synergy is essential in making casting secure, especially at the complex modeling stage. The latter must be articulated in such a way as to predict the behavior of the mold when it is used and ensure that the finished piece conforms completely to the model that generated it. As a result, a key factor in the system's flexibility is the "cycle by phases." This allows not only programming of individual stages through the definition of parameters (pressure, speed, etc.), but also their sequencing and articulation, without any a priori restrictions. In short, the entire cycle can be programmed to meet the manufacturer's specific needs with regard to the type of article, the composition and state of the slip, the type of mold resin, and any special finishing procedures.
Furthermore, the mold features a fifth part that can be maneuvered along the third transverse axis using a combined rotary-transverse motion. This means it can follow a complex trajectory that allows even pieces with particularly complex designs to be made easily.
Integrating IntegrationIf machine-mold integration is important, then machine-machine integration is certainly no less so. In this case, de-molding can be activated with three different options designed to meet a manufacturer's specific needs: a servo-mechanical device, an automatic device, and a robot equipped to carry out other integrated functions (e.g., the application of rim glue), along with other various programs and accessories.
Finally, the new single-mold machine is controlled by a process control unit that constitutes a potential mutual resource for other linked units. These can include other single-mold modules (up to a total of eight) as well as other casting machines, thus advancing the hypothesis of multi-functional management. Additionally, all molds used on the new single-mold machine can also be used on the multi-mold machine, and vice versa.
When machine-machine integration is achieved, integration comes full circle and returns to its starting point-that of industrial programming, where time to market and just in time goals must be modified quickly to keep pace with the competition.
For more information about integrated manufacturing solutions, contact Sacmi's Whiteware Division at Via Selice Prov.le 17/a, 40026 Imola (Bologna), Italy; (39) 0542-607111; fax (39) 0542-642354; e-mail firstname.lastname@example.org, email@example.com or firstname.lastname@example.org; or visit http://www.sacmi.com.
*The AVM, developed by NIV, a company in the Whiteware Division of the Sacmi Group.
**The AVE, also developed and supplied by NIV.