Dimensional Stability and Process Capability of an Industrial Component Injected with Recycled Polypropylene

Abstract

The usage of recycled polymers for industrial purposes arises as one of the most promising methods of reducing environmental impact and costs associated with scrapping parts. This paper presents a systematic study of the dimensional stability of a raw and 100% recycled polypropylene subjected to realistic environmental conditions occurring along its working life. The component studied is an internal part of an induction hob assembly. Industrial samples manufactured with both materials, in the same mold, and in the same injection machine, are subjected to ejection conditions, storage conditions (50 °C), and extreme performance conditions (80 °C). Induced dimensional changes are registered and analyzed using a coordinate measuring machine, and a tactile sensing probe. To verify the process capability of the samples manufacturing, Cp and Cpk values are calculated to evaluate the suitability of the recycled material as an alternative. Results conclude that, although the use of recycled material implies slight differences in terms of dimensional stability due to the changes induced in the polymer structure, these differences are not significant enough to affect the injection process capability. Therefore, recycling arises as one effective method to reduce both overruns associated with the consumption of raw polypropylene material and its environmental impact.

System Performance and Process Capability in Additive Manufacturing: Quality Control for Polymer Jetting

“…Based on the requirements, the target for C pk is very often established at a minimum of 1.67. Some of the industry manufacturers accept even lower values of 1.33 for C p and C pk [51]. Even so, the result for the height characteristic in terms of C pk was lower than 1.67 or 1.33.…”

Optimisation of Shrinkage and Strength on Thick Plate Part Using Recycled LDPE Materials

“…So far, this optimisation method has only been applied by a few researchers to increase part quality (in terms of tensile properties) using recycled plastic material [ 24 , 25 ]. Meanwhile, most research has only focused on changes in material properties due to variations in the ratio of recycled materials mixed with the virgin materials [ 18 , 19 , 20 , 21 , 22 , 25 , 26 , 27 , 28 , 29 ]. Therefore, it is necessary to conduct deep research in order to determine the full potential of reusing recycled material, especially post-industrial waste, which is easy to control from mixing with other types of materials.…”

Analysis and Economic Evaluation of the Use of Recycled Polyamide Powder in Masonry Mortars

“…At present, there is an international agreement about the necessity of sustainable development with the aim of a more efficient employment and management of the limited natural resources, which includes the promotion of recycling and reuse of waste materials [ 1 ]. For plastics and polymers, which are two of the main industrial byproducts and home waste materials [ 2 ], various processes are being conducted to reuse and recycle them, such as mechanical recycling (secondary polymers are obtained through mechanical processes), chemical recycling (monomers are recovered to be employed as new virgin polymers or are transformed in other useful materials), and energy recovery (energy is obtained from the combustion of post-consumer plastics) [ 3 , 4 , 5 , 6 , 7 ]. Additionally, the introduction as fillers in other materials is becoming a possible solution for plastic and polymeric waste materials, especially in construction materials, with examples of reuse in various structural materials, such as concrete [ 8 , 9 , 10 , 11 , 12 , 13 ], mortars [ 14 , 15 , 16 , 17 , 18 ], bituminous materials for pavements [ 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 ], and gypsum [ 31 , 32 , 33 , 34 , 35 , 36 ].…”