Conforming to Complex Mold Surfaces

Injection mold designers have been using a technique called “conformal cooling” for many decades. Mold temperature in the majority of injection molds is regulated through water lines (or steam or oil), which are typically drilled into the mold halves along straight pathways. However, this method limits the proximity of cooling to certain steel features. Conformal cooling, on the other hand, is an option that allows water channels to closely “conform” to complex mold surfaces.

Direct Metal Laser Sintering (DMLS)

Direct Metal Laser Sintering (DMLS) has made conformal cooling much more feasible in the past two decades. DMLS is an additive manufacturing technology that builds up geometries layer by layer, sintering each subsequent layer to the other. Another available technology is Selective Laser Sintering (SLS), which is distinct from DMLS but still a viable choice. Initially, these technologies were only viable for prototypes or low-volume applications. However, advancements in equipment and steel production now allow for mold components made through DMLS or SLS. What are the benefits of employing conformal cooling?

DMLS, SLS, and other emerging 3D technologies for metals are faster and more accurate than what was available even two years ago and require less, if any, final machining.

More uniform part cooling and fewer hot spots. From the injection processing perspective, this is the big payoff that drives everything. Uniform and effective cooling eliminates hot spots that can harm part quality and narrow processing windows.

Cooling is the largest portion of most injection cycles and a reduction of up to 50% can have quite an impact on overall cycle times. This efficiency translates into better use of available capacity, whether in relation to a press or tooling, including faster cycle times which are directly linked to reduced costs.

Uniform cooling means better and more consistent control of shrink, tighter Cpk’s, wider processing windows, smoother validations, reduced program risk, and less scrap. All these items taken together add up to a considerable reduction in overall costs even when stacked up against sometimes higher initial tooling investments.

Conformal cooling is seen by PTA Plastics as an increasingly viable choice for a wider range of applications, and we have decades of expertise in this method. Tools that utilize conformal cooling require a bit more attention than traditional tools, which makes this particularly important. Plugged pathways caused by corrosion can be challenging to fix. PTA has purchased equipment to treat and descale cooling lines, minimizing the need for expensive component replacements. Having dealt with blocked paths before, we understand the importance of this issue.

We, at PTA Plastics, are committed to staying up-to-date with the latest advancements in 3D steel manufacturing techniques. These techniques not only enhance conformal cooling, but they also improve various aspects of injection mold manufacturing, such as lead times, component quality, and strength, among others. The speed at which change occurs is rapid, and our commitment is to maintain our position at the forefront of these changes as well as other emerging technologies.