Thermal specification of 3D printed injection moulds made from PA12GB

This paper deals with the usage of the injection mould made from the plastic material. This technology is rapidly decreasing the time, necessary to the production of the prototype. This attribute takes nowadays a key role in the industry, especially in the automotive. Technology of using injection moulds from the plastic material (produced by additive technologies) has advantages in the decreasing of the time demands and cost reduction during the production of the prototype part. Unfortunately, plastic moulds have worse surface quality, lower lifetime of the mould (measured in number of produced parts) and more difficulties of moulding process regulation with respect to the metal moulds. This paper is focused on the injection process and it is describing the thermal distribution and specification of the comparable plastic specimen during injection into the metal and plastic mould. The results are the temperature and cycle-times comparisons. The effectivity of cooling is also compared in this work. It is obvious, that the plastic mould has worse results compared to the metal mould. However, this is clearly balanced by the speed of production and price of plastic mould. The prototype of the plastic mould was made from the material PA12GB with usage of 3D printer HP MJF4200

Comparison of microstructure and mechanical properties of plastic mould steel for physical application

In this paper, plastic mold steel S136 and S136 SUP were studied for microstructural observation and mechanical properties through metallographic, SEM, EDS, XRD, hardness test and impact test. The results showed that after the same heat treatment, the martensite structure of S136 SUP was denser, the carbides were more uniform and finer, and the hardness was slightly lower but the toughness was greatly increased compared with that of S136. the residual austenite content of S136 and S136 SUP were 2.46% and 10%, respectively, and the heat treatment hardness was 50.1 HRC and 49.1 HRC, respectively. The impact toughness was 90.6 J and 299.1 J.

SUBSTITUTES FOR MOLASSES AND CEMENT IN UREA-MOLASSES BLOCKS FOR RUMINANT ANIMALS

The first of two experiments was conducted to substitute cassava starch for molasses at levels of between 0 and nutrient blocks are discussed. 100% in urea-molasses blocks in six treatments. In a second experiment, of Gliricidia sepium, Leucaena leucocephala Gmelina arborea and cement were included at 15% levels respectively as substitutes to cement as feed block binders. A fifth treatment combined cement and the various leaves as binders. Parameters monitored included block hardness, stability in water, colour, storability, nutrient quality and cost. Results showed that the blocks dried within 3 - 7 days and the weights of the blocks progressively decreased (P<0.01) within the drying period, Final block weights were 88 to 97.5% of initial weights. The crude protein contents of the 100% molasses blocks were lower while the fibre contents of the leaves - substituted blocks were higher (P>0.05) between 25 and 28% CP. The blocks were strong and did not dissolve in water for 3 to 5 days. Increasing levels of cassava starch substitution made the blocks harder, Block colours varied from dark brown to dirty white. Use of leaves as binders reduced the cost of the blocks by as much as 20%. Blocks stored better when the sides of the plastic mould were lined with cellophane paper. The cassava substituted blocks stored up ic 9 months without moulding. Gliricidia sepium leaves, however, served as a good binder just like the other two leaves types used. aThe implication of using cassava starch and browse leaves in urea-molasses multinutrient blocks are discussed.