Choosing an IMS PCB Supplier: Review the Entire Heat and Isolation Path

An insulated metal substrate, or IMS, combines conductors, an insulating dielectric and a metal base in a specified construction. Selecting an IMS PCB supplier requires reviewing both heat transfer and electrical isolation. A claim that a board uses aluminum or has a high-conductivity material does not define the complete performance.

Map the path beyond the PCB

Identify how heat moves from the component through its attachment, board construction and mechanical interface to the cooling arrangement. Record where temperatures or thermal performance will be evaluated. A material property cannot by itself predict the temperature of a complete product.

TCLAD’s dielectric information lists several formulations and thicknesses, with thermal and electrical properties reported separately. That illustrates why the dielectric must be named and reviewed, rather than hidden behind a generic “metal-core PCB” description.

Give suppliers a complete construction request

• Define the conductor layer and copper requirements.
• Identify the dielectric grade and thickness.
• Specify the metal base and mechanical dimensions.
• Describe mounting holes and exposed metal regions.
• State electrical isolation and inspection requirements.
• Provide the intended thermal interface and assembly information.

Confirm how the circuit layer is isolated from the base around holes, edges and mounting features. Do not assume the base is automatically ground or that every mounting screw can contact it without affecting the product’s electrical design.

Compare evidence, not headline conductivity

Ask candidates to review the actual geometry and identify deviations. Compare material data under compatible definitions and conditions. A higher thermal-conductivity number can be misleading if dielectric thickness or the external mounting interface also changes.

Separate the material supplier from the board fabricator and assembler. Confirm who controls the dielectric selection, machining, surface finish and attachment process. Obtain current capability information for the proposed production site and order quantity.

Qualify the assembled thermal arrangement

Use representative components, mounting hardware and cooling interfaces during evaluation. Record ambient conditions, operating load and measurement locations. A test on an unsupported bare board cannot demonstrate the same behavior as an installed assembly.

Keep thermal results separate from electrical isolation evidence, while preserving their common construction identity. Review both when a material, thickness, mounting method or assembly process changes.

For repeat orders, require approval of substitutions that affect the qualified system. A shortlist of suppliers in China or another region becomes useful only after each candidate has answered the same construction and verification questions.

Primary reference: TCLAD’s IMS dielectric material information. See the metal-core PCB guide and aluminum PCB guide for defining the initial request.