What are the best practices for using 3D prototyping to create molds for casting and injection molding?

In the context of medical simulation, SLS printing with inelastic polymers has the advantage over SLA of an inherently rough surface (unless you’re also vapor smoothing), which results in cast silicone parts having a vaguely skin-like texture. Since aesthetics are a top priority in producing high-fidelity simulations, this bonus side effect of SLS means that we don’t have to add a skin-texture-surfacing workflow to nearly every mold part we create, saving us tons of time. SLA parts, on the contrary, have very smooth surfaces and casting silicone would result in an equally smooth texture, which also has its uses.

In the past couple years TPMS and generative lattices became popular for their ability to lightweight while conserving mechanical strength. The main downside is post processing — all those little internal nooks and crannies trap un-sintered powder, and without exhaustive manual media/water blasting the part may continue to shed microplastic particles indefinitely, which isn’t safe for many medical applications. TPMS therefore has the advantage over, say, a Voronoi lattice because the most common triply periodic lattices like Gyroid or Diamond are guaranteed to have fewer powder-trapping features. However, other non-periodic lattices like Spherenes appear to overcome this problem.

Alguns dos benefícios do uso de prototipagem 3D para fabrica??o de moldes de inje??o s?o: ?Economia de tempo: a prototipagem 3D é mais rápida do que os métodos tradicionais de usinagem, podendo reduzir o tempo de produ??o entre 50% a 90%. ?Valida??o de projeto: a prototipagem 3D permite testar e verificar a geometria, a fun??o, a ergonomia, a textura, a resistência e a degrada??o dos componentes plásticos antes de fabricar o molde definitivo. ?Inova??o de produto: a prototipagem 3D permite criar e recriar livremente as pe?as, superando as limita??es da manufatura tradicional e possibilitando o desenvolvimento de produtos mais complexos e detalhados.

A bench top injection molder and printed injection molds are a key part of a budget friendly r&d but can limit use of materials with higher melting temperatures. High temperature and rigid 10k resin are decent choices for printing, and post processing to ensure mold surfaces are sanded flat enough so light cannot be seen when put together will help limit flashing. Don't forget to preheat the mold and design in vents.

Casting and molding are examples of traditional “soft tooling” methods for producing multiples of parts. Casting is generally good for lower volumes (ie a single silicone mold can often make 15-25 cast parts), while injection molding is typically used for much higher volumes. Recent advancements in additive manufacturing can change the historical rules in selecting a manufacturing process: For example, new materials make it possible to 3D print a temporary injection mold tool, making injection molding economical, even in very low volumes. Additionally, some new additive technologies offer the required throughput, aesthetic, performance, and economics to make it possible to skip tooling all together, most commonly in volumes of 1-1000’s.

Escolher o material certo para melhor troca térmica do molde de inje??o é uma decis?o importante que pode afetar a qualidade, a produtividade e o custo das pe?as plásticas. Existem vários fatores que devem ser considerados na hora de escolher o material do molde, cavidades ou impress?o, como: O tipo e a quantidade de pe?as que ser?o produzidas; O acabamento superficial e a precis?o dimensional das pe?as; A resistência ao desgaste, à corros?o e à fadiga do material; A usinabilidade e a temperabilidade; A condutividade e a estabilidade térmica do material. Em geral, os materiais mais usados para moldes de inje??o s?o os a?os e o alumínio. Cada um deles tem vantagens e desvantagens, dependendo da aplica??o e das exigências do projeto.