Cutting conductive silicone gaskets

The processes side by side

Each process below is published for conductive elastomer sheet by a maker or by a fabricator that cuts it. The table is our summary of how each one cuts and what that does to the part, with the sources for each row; the sections after it give the figures.

Lasers are a fifth route some converters list for thin EMI parts, but fabricators disagree about them on silicone. One reports charred, melted or burnt edges when rubber is laser cut, and another says silicone cuts poorly and charring can be an issue [10][9]. We found no maker data on laser-cut metal-filled silicone, and Conquest Seal does not laser-cut it.

What a pure-water waterjet does to conductive sheet

A pure-water waterjet cuts with water alone through an orifice 0.003 to 0.020 in across, and a waterjet maker's glossary puts the pure-water kerf at 0.003 to 0.015 in [3]. It is a cold process: a second waterjet maker states that there is no heat input and so no burning or heat-affected zone, and lists rubber among the heat-sensitive materials a waterjet cuts [4]. For conductive silicone that means the binder at the cut edge is not melted or charred, which is the complaint fabricators make about lasers on rubber [9][10]. A fabricator that runs both processes reports that the waterjet leaves a cleaner edge on thick rubber, without the concavity of die cutting [5].

Three things the cut does not change. The filler, the binder, the type letter, the lot and the volume resistivity belong to the sheet as its manufacturer made and tested it, before anyone cut it. The thickness and its tolerance come from the molded sheet too: the Parker Chomerics® handbook gives plus or minus 0.004 in at 0.020 in thick, rising to plus or minus 0.010 in at 0.093 and 0.125 in [1]. And the cut edge is bare filler whichever process makes it; the 2000 handbook lists a die-cut silver-aluminum edge as its own entry in its galvanic potentials, so the edge still needs the flange-finish planning in the galvanic compatibility guide [2].

What is not published: we found no maker or fabricator data on whether contact with water during cutting changes the conductivity of a silver- or nickel-filled edge, and no drying procedure written for conductive parts. This page therefore makes no claim either way. If your drawing sets an edge resistance or a resistivity check after cutting, put it on the drawing so the quote addresses it.

Tolerance: what makers and fabricators publish

For flat die-cut conductive elastomer gaskets the maker's handbook gives plus or minus 0.010 in on overall dimensions up to 10 in, plus or minus 0.020 in from 10 to 15 in, and plus or minus 0.20 percent of nominal above 15 in [1]. Overall dimensions there include every feature-to-feature dimension, edge to hole and hole to hole [1]. The same handbook notes that flat die-cut and molded gaskets vary in the unrestrained state, and that inspection fixtures are common for checking finished parts [1].

No maker publishes a waterjet tolerance for conductive sheet. Rubber fabricators publish their own for their machines: one gives plus or minus 0.010 in under 12 in and plus or minus 0.020 in over 12 in for waterjet-cut sponge and foam, against plus or minus 0.015 in and 0.030 in for die-cut [8]. Another reports plus or minus 0.010 in on thick sponge and on solid rubber over 1 in thick [5]. Waterjet machine makers also quote accuracy: one gives plus or minus 0.003 to 0.005 in as a common general tolerance for abrasive waterjet parts finished alongside wire EDM [4]. That is a figure for machined parts; the fabricators' figures above are the ones given for rubber.

Conquest Seal publishes no tolerance figure of its own on this page. Put the tolerance your part needs on the drawing, and the quote confirms whether the waterjet holds it or the part goes to a die.

The smallest features

The handbook's limits for die-cut conductive parts are a maximum size of 32 by 32 by 0.125 in and a width never less than the gasket's thickness [1]. The notes to a fabricated gasket drawing in its 2000 edition add that the wall between a hole and an edge should equal the elastomer thickness, and a hole should be no smaller than that thickness [2]. Where bolts pass through the gasket into the shielded compartment, the holes must fit the threads closely; the handbook says that needs machined dies rather than rule dies, or an EMI seal under each bolt head instead [1].

A waterjet needs no die, so the die rules are not a tooling limit for it. We found no published minimum web or bridge width for waterjet-cut rubber, so the width-at-least-thickness rule above is the only published figure for conductive sheet. A narrower web is a question to put on the drawing.

Adhesive backing and kiss cutting

Conductive sheet can be bought with a pressure-sensitive adhesive laminated by the sheet maker: the handbook offers a thin acrylic, electrically conductive adhesive on its silicone and fluorosilicone sheets 0.020 in thick and up [1]. Its published electrical figures are for sheet without adhesive, it advises against adhesive where the lowest resistance matters, and it gives sheet with adhesive a shelf life of one year from manufacture against an indefinite one without [1]. The adhesive-backed EMI gasket guide covers the constructions, the shielding penalty and the temperature limits.

A kiss cut goes through the elastomer and the adhesive but stops at the release liner, so the parts stay on a carrier for peel-and-place or pick-and-place assembly [7]. The compounder that describes it does it with dies [7]. A waterjet cuts through everything under the stream, liner included, so it cannot stop at the liner. So Conquest Seal cuts adhesive-backed conductive sheet on its waterjet with the liner on, each part on its own piece of liner, and sends parts that must be kiss-cut on a continuous liner to a cutting partner.

Which process the sources point to, by job

No process wins everywhere. The rows below are what the cited makers and fabricators say each process is for; your drawing and your quantity decide.

How Conquest Seal cuts conductive sheet, and what to send

Conquest Seal cuts conductive silicone and fluorosilicone sheet on its own pure-water waterjet in Orange, California. When the drawing calls out MIL-DTL-83528, the sheet comes from manufacturers on the QPL-83528 list. The cut adds your outline; the material, its type letter and its lot stay the manufacturer's, and the certificate of conformance that ships with every order names the part number, the specification, the manufacturer, the lot and the quantity. Conquest can also supply the sheet maker's certification on the raw material. Molded O-rings and shapes, extruded profiles and spliced rings are supplied from the manufacturers, and die-cut parts and parts kiss-cut on a continuous liner go to a cutting partner.

• The drawing as a DXF, DWG or PDF, with the tolerance your part needs written on it.
• The sheet thickness, from the thicknesses on the conductive silicone sheet page.
• The filler and binder, or the MIL-DTL-83528 type letter your drawing names; the MIL-DTL-83528 guide explains the letters.
• Adhesive yes or no, conductive or not, and whether the parts ship loose or kiss-cut on a liner.
• The quantity, and the paperwork the order needs.

Send them through request a quote and a person replies within one business day. The custom gaskets page covers waterjet cutting for every other sheet material, and the EMI gasket forms guide compares cut sheet with molded, extruded, form-in-place and mesh gaskets.

Chomerics is a trademark of Parker Intangibles LLC, a Parker Hannifin company. No affiliation or endorsement is implied.

Sources

1. [1] Parker Chomerics, Conductive Elastomer Engineering Handbook, MS EN 111616, Edition II (2016): PSA backing pp. 29 to 31, die-cut limits p. 18, bolt holes and dies p. 17 and flat die-cut tolerances p. 74; https://www.parker.com/content/dam/Parker-com/Literature/Chomerics/Parker-Chomerics-Conductive-Elastomer-Engineering-Handbook.pdf; read 2026-09-24.
2. [2] Parker Chomerics, EMI Shielding Engineering Handbook, November 2000 edition (distributor-hosted copy): gasket design notes, galvanic potentials and fabricated-gasket drawing notes; https://sealingdevices.com/wp-content/uploads/2022/02/CHO-HB.pdf; read 2026-09-24.
3. [3] Flow International, Waterjet Dictionary (orifice, pure waterjet, kerf and taper entries); https://www.flowwaterjet.com/explore/waterjet-basics/waterjet-dictionary; read 2026-09-24.
4. [4] OMAX, How Does Waterjet Cutting Compare to Other Cutting Methods?; https://www.omax.com/en/learn/waterjet-cutting-compared/; read 2026-09-24.
5. [5] Stockwell Elastomerics (a fabricator), Waterjet Cutting; https://www.stockwell.com/waterjet-cut-gaskets/; read 2026-09-24.
6. [6] Stockwell Elastomerics, EMI Shielding Materials, Electrically Conductive Silicone; https://www.stockwell.com/emi-shielding-materials/; read 2026-09-24.
7. [7] Specialty Silicone Products (a compounder), Die Cut EMI Gaskets and Materials; https://sspinc.com/emi-gaskets/die-cut-emi-gaskets/; read 2026-09-24.
8. [8] NEDC (a fabricator), Die-Cut and Waterjet Cut Tolerances for Sponge and Foam Gaskets, 23 September 2025; https://www.nedc.com/thickness-tolerance-die-cut-and-waterjet-cut-tolerances-for-sponge-foam-gaskets/; read 2026-09-24.
9. [9] NEDC, Die Cut Gaskets vs. Laser Cut Gaskets vs. Waterjet Cut Gaskets, 5 April 2020; https://www.nedc.com/die-cut-gaskets-vs-laser-cut-gaskets/; read 2026-09-24.
10. [10] Stockwell Elastomerics, Laser Cut Gaskets vs. Waterjet Cut Gaskets; https://www.stockwell.com/laser-vs-waterjet-cut-gaskets/; read 2026-09-24.