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How to Spec Drive and Inverter Insulation: What to Send H-O for a Quote
Insulation and TIM parts attract underspecified RFQs because the part looks simple: a rectangle with holes, a pad on a liner, a strip of film. What the quote actually prices is the duty hiding behind that geometry: whether the interface must isolate, how big the real gap is, how much clamping force exists, and how hot the location runs.
This is the ten-item checklist the H-O applications team works from for insulating TIM pads, gap fillers, adhesive films, dielectric barriers, and harness wrap, drawn from the parent application page's own engineering-review list, plus what engineering does with each item and what comes back.
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The ten things to send, and what each decides
| Send this | What it decides |
|---|---|
| 1. Electrical role of the interface | The fastest filter on the whole page: isolating interfaces restrict the choice to the insulating families; grounded interfaces admit electrically conductive graphite, which usually wins the thermal comparison there. |
| 2. Working voltage and isolation context | The dielectric class the grade must support, verified per ASTM D149 on the TDS, with the working margin carried by your insulation coordination per the IEC 61800-5-1 framework. |
| 3. Worst-case gap and flatness | Reinforced pad versus gap filler. Component height spread, baseplate bow, and torque spread open the nominal gap; the filler is sized to the worst case, not the drawing nominal. |
| 4. Clamping force, or its absence | Pads need clamping force to work; where hardware is absent or crowded out, the answer moves to a thermally conductive adhesive film, which is a permanent assembly decision. |
| 5. Thermal-resistance budget | Candidates are compared per ASTM D5470 thermal-impedance data at your pressure and thickness, not by the headline W/m·K column. |
| 6. Service temperature at the interface | The local hot spot, not the cabinet ambient, including adjacency to magnetics and busbars. Films and papers are framed by insulation thermal class per IEC 60085. |
| 7. Flammability class requirement | UL 94 ratings are per grade, not per family; if the program requires a class, the grade whose TDS shows it is selected and the TDS stays with the order file. |
| 8. Assembly method and liner presentation | Kiss-cut on liner for peel-and-place, tab placement, lamination order, slit-roll width for wraps. These decide line speed more than the material does. |
| 9. Geometry: DXF, STEP, or PDF, or a sample part | The footprint, fastener clearances, and cut-outs that become the die or CNC program. A worn sample part works when no drawing exists. |
| 10. Prototype and production volumes | Converting method and price structure. Every part is made to order; prototype quantities through full production runs are equally accepted, and MOQ varies by material and part. |
What engineering does with the list
Items 1 and 2 frame the electrical problem and remove whole families before any thermal talk. Items 3 through 5 pick the construction: a thin reinforced insulator (PROTECT pads, Sil‑Pad TSP grades) for flat clamped joints, a soft Gap Pad filler for uneven stacks, a SECURE adhesive film where fasteners are absent, or eGRAF graphite where item 1 said the joint is grounded.
Item 6 filters by TDS service range and thermal class; item 7 checks the UL 94 line on the specific grade. Items 8 and 9 become the converting plan: die-cut footprint with fastener clearances, kiss-cut-on-liner presentation, lamination order for multi-layer parts such as a dielectric film bonded to a thermal pad, or slit widths for aramid-paper harness wrap. Item 10 sets method and pricing.
The reply cites the selected grade's TDS values with the method named, and flags anything the checklist left open.
What happens after you send it
- Drawing review. Engineering reviews the interface against the vendor TDS: electrical isolation requirement, dielectric margin, gap and flatness, thermal-resistance budget, service temperature, and clamping or bonding method.
- Material direction and quote. A family and grade direction with the TDS attached, the converted format (die-cut, kiss-cut on liner, laminated), and pricing at your quantities.
- Samples. Typically 3 to 5 business days for common die-cut configurations on materials we keep on hand.
- Production. Standard runs ship about two weeks after drawing approval, including kiss-cut-on-liner and laminated configurations; expedited service is available. Ongoing parts run with material traceability and lot-code TDS records.
Documentation available on request: material technical data sheet, certificate of conformance, lot traceability, and first-article inspection, under our ISO 9001:2015 certified quality management system. H-O is a die-cut converter, not a raw-material producer: we do not manufacture the raw films, pads, or papers, and we do not independently certify them; assembly-level outcomes belong to the finished equipment's standards (IEC 61439 / UL 508A for the enclosure, IEC 61800-5-1 for the drive).
The mistakes this checklist prevents
| Spec mistake | What it causes | Checklist item that catches it |
|---|---|---|
| Geometry-only RFQ | A quote for a rectangle, not an insulation part; electrical review impossible | Items 1 and 2 |
| Conductivity-first selection | Graphite on an isolated interface, or a thick filler on a flat joint | Items 1, 3, and 5 |
| Nominal gap on the drawing | Pad bridges the real stack; contact area collapses; junction climbs | Item 3, toleranced honestly |
| Flame class assumed family-wide | UL 94 listings are per grade; the audit finds a TDS without the class | Item 7 plus the TDS check |
| Wrap classed to cabinet ambient | Harness wrap ages out beside a hot module | Item 6, the local hot spot |
| Liner and tabs left to the shop floor | Line-speed surprises at assembly; rework on a permanent adhesive film | Items 4 and 8 |
Frequently asked questions
What if I do not know the worst-case gap?
Send what you do know: the stack drawing, the component heights, and the baseplate or sink flatness callout. Engineering can frame the gap question from those, and a conformable gap filler's thickness band is chosen to cover the credible worst case at your clamping force. The parent page's failure-modes section shows both directions of guessing wrong, which is why the honest answer to this item is worth more than a precise-looking nominal.
Can H-O cross-reference the TIM or insulation grade on my print?
In most cases, yes. If your drawing calls out an insulating TIM, gap filler, adhesive film, or dielectric material by a brand part number, engineering identifies a comparable grade from the lines we convert, matching on electrical role, dielectric class per ASTM D149, thermal impedance per ASTM D5470 at your pressure, thickness and softness, service temperature, and flammability rating. It is an industry cross-reference, not a guaranteed drop-in, verified against the vendor TDS before quoting.
Does H-O make these materials, or convert them?
H-O die-cuts and converts. We take roll and sheet stock from the material manufacturers and die-cut, CNC knife-cut, kiss-cut on liner, slit, and laminate it to your drawing; we do not manufacture the raw films, pads, or papers in-house. What we do in Winsted, Connecticut is precision conversion: pads cut to the module footprint with fastener clearances, kiss-cut-on-liner formats for assembly lines, and multi-layer laminations, with material traceability and lot-code TDS records.
What lead time should I expect for samples and production?
Every insulation part is made to order, including samples. Samples typically ship in 3 to 5 business days for common die-cut configurations on materials we keep on hand; standard production runs ship about two weeks after drawing approval, including kiss-cut-on-liner and laminated configurations; expedited service is available when timing is critical. MOQ varies by material and part, and prototype quantities through full production runs are equally accepted.
Send the checklist, get a drive-insulation quote
Attach the geometry and as many of the ten items as you have. If something is unknown, say so; the review proceeds with the assumption flagged.
Samples typically ship in 3 to 5 business days for common die-cut configurations on materials we keep on hand; standard production runs about two weeks after drawing approval; expedited service is available. MOQ varies by material and part.
Family-owned in Winsted, Connecticut since 1971 · ISO 9001:2015 certified · OEMs worldwide send us a drawing — and get back their part.
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Send H-O your drawing or describe the part—engineering reviews every RFQ and converts samples on your geometry.
Last updated · Reviewed by H-O Products engineering (ISO 9001:2015 certified converter, Winsted, CT).
References
- ASTM D5470 (thermal impedance at pressure, the comparison basis for TIM candidates); ASTM D149 (dielectric strength); ASTM D2240 (hardness).
- UL 94 (flammability classifications, per grade); IEC 60085 (insulation thermal classes); IEC 61800-5-1 (drive insulation framework); IEC 61439 / UL 508A (enclosure assembly standards).
- Manufacturer technical data sheets for the insulating TIM, gap-filler, adhesive-film, graphite, film, and paper grades named on the parent application page.
This checklist supports a quotation workflow; it does not constitute design guidance for any specific drive, and dielectric working margins belong to your insulation coordination per the IEC 61800-5-1 framework. Grade-level values are confirmed on the manufacturer's current technical data sheet at quote time. All parts are custom manufactured to order; minimum production run quantities vary by material and part. H-O is a die-cut converter, not a raw-material producer, and does not certify finished drives or enclosures.