Pictured is a computer rendering of the plastic tub for Merloni's TOP 2001 washing machine. Merloni and Meccanica Generale co-designed this tub, which allowed Merloni to use less expensive materials and simplify the assembly process, while maintaining a high level of quality.
In the European
appliance market, approximately two-thirds of washing machines produced use
plastic for the washing machine tub, and the number is expected
to grow. A variety of factors influence this trend, including greater freedom
of design, which in turn allows greater flexibility in designing and integrating
other parts; the noise and energy reductions since plastic is lighter weight
and flexible; and the ease of recycling plastic parts. Additionally, the
competitive washing machine market demands that producers offer quality
performance while maintaining prices, and plastic helps meet that goal.
When appliance company Merloni Elettrodomestici (Fabriano,
Italy) began development of the TOP 2001 top-loading washing machine with
the goals of reducing the
weight and improving the productivity of its previous top-loading washer,
the company knew plastic would be part of the picture. Also, because the
competitive marketplace means that producers cannot afford to have a lengthy
development time to avoid costly setbacks, Merloni knew it would turn to
a plastics specialist for help in designing the TOP 2001.
a plastic parts specialist and injection mold manufacturer also located in
Ancona, Italy, proved to be the ideal partner for the development
of the new washing machine. The two companies, which have worked together
on various projects since 1993, chose to use the co-design approach. Explains
Mr. Montevecchio, Sales and Marketing director at Meccanica Generale, "The
co-design approach makes the most of the synergy coming from complementary
experiences and skills. Furthermore, the possibility [of cooperating] with
a partner able to work out the milestones of the product development phase
usually results in shorter lead time, reduced project management cost, and
reduced risk of unexpected modifications."
Mr. Dino Bongini, Research and Development manager at Merloni's Brembate
plant in Bergamo, Italy, confirms, "[The co-design process] reduces time
to market and, because maximum know-how is involved from the beginning, [it]
minimizes modifications." Together, Merloni, led by Mr. Bongini, and
Meccanica Generale defined technical specifications and market needs and
created a preliminary model of the tub. Meccanica Generale then created 3D
finite element models and testing began.
The partners worked in close cooperation throughout the structural
and rheological computer simulations, which aimed to verify the balancing
of the tubs and
positioning of the counterweights; locate the most stressed areas; define
the optimal geometry in terms of weight/performance ratios; check the dynamic
behavior of the washing unit and its interaction with the base; and analyze
the geometry of critical areas such as the damper and spring fixation.
A mold flow study was performed as well to help analyze and improve the injection
process with the goal of achieving maximum productivity.
The weight/performance ratio was particularly important, as both companies
wanted to use the plastic material PP+40%CaCo3, which costs half as much
as PP+30% glass fiber, the standard material used in plastic tubs.
Of course, Merloni was not willing to sacrifice performance in order to use
the cheaper material; the tub still had to perform optimally at speeds up
to 1,200 rpm. Meticulous simulations and the depth of experience available
due to the co-design process were said to have contributed to meeting this
goal. The tub does indeed utilize the PP+40%CaCo3, offering a significant
competitive advantage, according to Mr. Bongini. He explains, "[With
PP+40%CaCo3], the process and the costs are better. Specialized design helps
the final product to be as high quality or better [than with PP+30% glass
The finished product includes a washing tub and related base made of plastic.
The two parts are linked by dampers. Due to this design, the cabinet in the
TOP 2001 is said to have limited structural function, allowing a lighter
cabinet and easier assembly. These modifications helped achieve the major
goal of this project: to achieve the highest performance possible while reducing
expenses by using the least amount of material and streamlining assembly.
Meeting this goal was important because every cost savings counts in the very
competitive washing machine market. Explains Mr. Montevecchio, "[There
is] very strong competition to reduce the cost of the washing unit, [while
keeping] high performance. This means the development stage must be very
accurate, in order to calculate the best geometry to reach the specifications
with the lowest weight." An additional competitive advantage was gained
because the entire process took only 18 months - critical timing, according
to Mr. Bongini, who says that a shorter time to market was one of the main
reasons for embarking on the co-design with Meccanica Generale in the first
In this partnership, the co-design approach seemed to produce results. At
Merloni, production of the molds is far higher than production of the previous
This is currently the highest production in the market for this type of mold,
according to Mr. Montevecchio.
At Meccanica Generale, the process opened the door for a new focus on providing
solutions for its customers. Says Stefano Mancini, Meccanica's Technical
Director, "Looking to the future, we have decided to further improve
our co-design approach by presenting to our customers innovative solutions
and ideas. For this reason, one of the main areas of activity of our Domestic
Appliances Technical Team is the Research and Design and Laboratory Test