What Is CTI 600?

CTI stands for Comparative Tracking Index.

It is a material property determined using standardized testing, such as IEC 60112, to evaluate the resistance of a solid insulating material to electrical tracking along its surface under specified test conditions.

In simple terms, a higher CTI indicates greater resistance to the formation of a conductive path on the material surface under the defined test conditions.

This makes high-CTI materials particularly relevant for electrical and electronic applications where insulation performance, creepage distance and compact packaging are important design considerations.

What Materials Can Achieve CTI ≥ 600?

CTI 600 is not a specific plastic material.

Different polymer families may offer specific grades capable of achieving CTI ≥ 600, depending on their formulation, reinforcement, fillers, flame-retardant system and other material characteristics.

Depending on the application and specific resin grade, high-CTI engineering materials may include:

Engineers should therefore not assume that every PPS or every PBT material has the same CTI performance.

Why Is CTI 600 Important for Power Module Housings?

Modern Power Module designs continue to become smaller while operating at higher voltages and power densities.

A typical Power Module Housing may incorporate multiple conductive components such as:

These conductive components may be located relatively close to each other within a compact plastic structure. The insulating material between them therefore becomes an important part of the overall electrical design.

Using a high-CTI material with CTI ≥ 600 can provide greater resistance to surface tracking and may support engineers when designing appropriate creepage distances according to the relevant standards and operating conditions.

Why High-CTI PPS for Power Module Housings?

PPS — Polyphenylene Sulfide — is widely used in demanding automotive and industrial electrical applications because selected grades can provide an excellent combination of:

For high-voltage Power Module applications, specially formulated high-CTI PPS grades with CTI ≥ 600 can combine the inherent advantages of PPS with enhanced tracking resistance.

This makes high-CTI PPS particularly attractive for components that must simultaneously manage electrical insulation, mechanical strength, dimensional accuracy and thermal performance.

Proven Experience with CTI 600 PPS Power Module Housings

Material selection is only the beginning.

Successfully producing a CTI 600 PPS Power Module Housing requires much more than simply selecting a high-CTI resin.

Ming-Li's practical manufacturing knowledge includes:

CTI 600 PPS Insert Molding: More Than Plastic Injection

Many Power Module Housings are not simple plastic components. They are complex metal-plastic integrated structures.

Copper busbars, terminals, nuts, pins and other conductive components may need to be accurately positioned inside the mold before high-temperature PPS is injected around them.

During molding, these inserts are subjected to injection pressure and thermal loading. Even a small displacement can affect:

For this reason, successful CTI 600 PPS insert molding requires careful consideration of both the plastic and metal components from the beginning of the mold-design process.

Ming-Li has extensive experience in insert molding and overmolding, including complex Power Module Housings with multiple metal inserts.

Moldflow Analysis for High-CTI PPS

High-CTI PPS grades, particularly glass-fiber-reinforced materials, can present molding challenges.

Material flow and fiber orientation can influence:

Gate location therefore becomes a critical engineering decision.

Before tooling is finalized, Moldflow analysis can help evaluate filling behavior and identify potential manufacturing risks.

Depending on the component design, Ming-Li can evaluate:

• Filling pattern
• Gate location
• Weld-line position
• Air traps
• Pressure distribution
• Fiber orientation
• Shrinkage
• Warpage
• Multiple gate concepts

For complex Power Module Housings, this analysis can help optimize the design before steel is cut and reduce unnecessary tooling modifications during the trial stage.

Precision Tooling for Power Module Housings

A high-performance CTI 600 material cannot compensate for an inaccurate mold.

Power Module Housings often require tight control of:

Ming-Li combines precision mold manufacturing with advanced CNC machining, EDM and metrology capabilities.

Our manufacturing capabilities include ultra-precision machining down to ±1 μm at the machining level, supported by high-end machining and inspection equipment.

For demanding Power Module Housing projects, this enables mold components and critical inserts to be manufactured and controlled to the precision required for stable injection molding.

CT Measurement and Dimensional Validation

Complex Power Module Housings can contain internal structures and embedded metal inserts that are difficult to inspect using conventional measurement methods alone.

Ming-Li uses advanced metrology equipment including ZEISS CT measurement technology, CMM and optical measurement systems to support dimensional validation.

Depending on customer requirements, our inspection capabilities can include:

CT inspection can be especially useful for evaluating internal structures, plastic wall thickness and the position of embedded metal components without destroying the molded part.

From CTI 600 PPS Tooling to Mass Production

For Power Module Housing projects, tooling capability and production capability should work together.

Ming-Li provides an integrated manufacturing process:

This integrated approach allows potential manufacturing issues to be considered from the earliest design stage rather than only after the mold has been completed.

Applications for CTI 600 Power Module Housings

High-CTI PPS and other CTI ≥ 600 engineering materials can be considered for a wide range of high-voltage power electronics applications.

Ming-Li Precision — Your Manufacturing Partner for CTI 600 Power Module Housings

For high-voltage Power Module applications, selecting a material with CTI ≥ 600 is important—but material selection alone does not guarantee a successful component.

The final result depends on the interaction between:

Ming-Li Precision combines these capabilities under one manufacturing system.

With more than 100 sets of Power Module Housing mold experience and actual manufacturing experience with CTI ≥ 600 PPS Power Module Housings, Ming-Li supports customers developing demanding IGBT, SiC, EV, charging and industrial power electronics applications.

From early DFM and Moldflow analysis to precision tooling, high-performance PPS molding, metal insert molding, CT inspection and mass production, our goal is to help customers move from design concept to stable production.