**4.1. Detailed analysis of assembled sub-systems components**

Regarding the assembled sub-systems of the machine-tool, and considering the trend for all electric or electromagnetic versions of these, particular attention should be given to the use of advanced functional materials, particularly composites, and the increased use of additional electronic components, as these typically includes higher amounts of hazardous materials or raw materials which are hard to recover. Also on this analysis, the sub-system approach for improvement is recommended in order to favour a finer analysis of all components. In fact, while the significant impact of a housing material can be more evident from the volumetric contribution of the component, only a detailed sub-system analysis can insure that the determinant impact of a small volume component based on a hazardous material would not be missed. Although some mandatory related legislation is established for electronic components, the amount and combination of substances in a multi-component electromechanical sub-system is still relying on the environmentally conscious of the sub-system manufacturer.

Towards Benign Metal-Forming:

The Assessment of the Environmental Performance of Metal-Sheet Forming Processes 147

represent less than 20% of the cost. In fact, polymer resins are the cost-drivers in these compositions. In general, epoxy resins are about four times more expensive than alternative polyester resins. Depending on the quality requirements, polyester could be a preferable choice, but they are less stable and present a higher shrinkage rate, which might be a problem in thicker bodies, as high shrinkage might result on significant internal stressing and subsequent cracking. Mineral casted structures can be produced in a single-step, and process time is mainly affected by the curing process, which depends mostly on the polymer characteristics (some products are presenting curing times up to 24 hrs at room temperature).

**Figure 5.** Comparative analysis of vibration dampening between conventional metals used in machine-

In turn, regarding the environmental benefits related to the introduction of polymer




tools and a commercially available polymer composite (based on Anocast product, a Rockwell

concrete-based solutions, the following aspects are to be highlighted:

re-used as filler to the new mineral casting composition.

25% of that needed to produce an equivalent welded steel structure;

Automation product (Rockwell, 2012)).

casting or welded steel parts;
