Custom Capabilities FAQs

The questions below come up most often when engineers start a custom interconnect project with us. For the full company-wide list, see our Frequently Asked Questions page. When you are ready to send us a requirement, the custom part worksheet captures the dimensions, materials, and quantities our engineers need.

Can Mill-Max make custom pin receptacles or connector assemblies?

Yes. Application-specific interconnects are what we do best. Whether it is changing a diameter, a length, or a hole size, we can produce exactly what is needed for your application. We turn custom products around quickly, at a reasonable price, and in many cases at a low minimum. About half of the products we supply are custom. Start by reviewing our standard offerings, or if you know the part number you want to change, start a modification to an existing part.

What is the minimum order quantity for a custom part?

There is no single minimum. The answer depends on which of our three custom manufacturing routes your design calls for, and the right route is usually decided by the design itself rather than by the quantity you have in mind. It is worth understanding all three before settling on one, because a change in approach can move the minimum considerably.

• Custom discrete pins, receptacles, and spring-loaded pins carry a minimum order of 1,000 pieces.This route covers both modifying one of our existing standard parts and producing a completely custom component with all-new features. Because these are machined rather than molded, no tooling investment is required to get started.
• Machined laminate connectors have no minimum quantity at all. These are produced from FR-4 or G-30 polyimide, machined rather than molded, so there is no mold tool to pay for. That makes this the natural route for prototype and design-concept builds, non-standard low-volume configurations, and genuine one-off requirements such as test fixturing. If you need a handful of parts to prove out a design, this is almost always where to start.
• Injection-molded connectors require a custom mold tool to be designed and cut before the first part is produced. That tooling is a fixed, up-front cost, so the economics generally make sense when your requirement is 10,000 pieces or more. Lower quantities can still be the right call when a design is too complex to produce as a machined laminate connector and molding is the only practical way to make the part.

What is the lead time on custom products?

Lead time depends on the complexity of your part. Where the requirement is mixing and matching standard pins into a standard insulator, turnaround can be as little as 3 weeks. Custom pins and receptacles typically ship in 5 to 7 weeks. Custom molds and machined laminate connectors vary the most and can run up to 12 weeks. Designs that require a custom spring take 12 to 14 weeks.

To get a design started, use our product finder to select the standard part closest to what you need, then click Customize this Part on the product details page. Starting from an existing part is also the fastest path, since it gives our engineers a defined baseline to work from.

Do I have to pay a tooling or NRE charge?

It depends on what is being customized, and in many cases, there is no charge at all.

• Discrete pins, receptacles and spring-loaded pins. Modifying an existing standard part, changing a diameter, a length, a hole size or a plating, generally does not carry an NRE charge. These are turned on the same high-speed machines that run our standard parts, so a dimensional change is a setup change rather than new tooling. The minimum order quantity is 1,000 pieces.
• Machined laminate connectors. No tooling charge. Machining the insulator from FR-4 or another laminate sheet avoids the cost of a mold tool up front, with no minimum order quantity this option makes prototype and low-volume custom connectors practical.
• Injection-molded connectors. A custom molded insulator does require a mold tool, which is a real up-front cost. It is the more cost-effective choice once volumes climb, and it is why we often recommend proving a design in machined laminate first, then transitioning to molding for production. Custom Connector Manufacturing compares the processes directly.
• Custom carrier tape. Where a part is not already offered on tape and reel, custom tape requires a nominal tooling charge to produce the pocket that fits it. It is a modest one-time cost, and worth raising early if automated placement is in your plans. See Carrier Tape Options for Mill-Max Discrete Pins and Receptacles.

Send us your requirement and we will tell you up front whether any tooling cost applies before you commit to anything.

What is the difference between a machined laminate insulator and an FR-4 custom connector?

They are the same thing. Machined laminate is the general term for an insulator milled from sheet stock rather than injection molded, and FR-4 is the laminate we use most often. Where you see machined laminate on our site, that is the FR-4 custom connector capability described in Introduction to FR-4 Custom Connector Assemblies. G-30 polyimide, FR-5, and G-11 epoxy are the higher-temperature laminates available through the same process.

What material thicknesses are available for a machined laminate connector?

Standard material thicknesses range from .010” to .500”, which covers most requirements. Milling in the X and Y axes holds tight positional tolerances for fine-pitch layouts, and Z-axis capability supports features such as steps, bosses, and pockets.

What options are available above 150°C?

Mill-Max offers high-temperature beryllium nickel equivalents to the standard beryllium copper contact clips, typically used in down-hole, burn-in, or similar applications where temperatures exceed 150°C. On the insulator side, G-30 polyimide and other high-temperature laminates go beyond the limits of FR-4 and G-10. See High Temperature Beryllium Nickel Contacts for the available substitutions.

Can Mill-Max hold tighter tolerances than the published specifications?

For some features, Mill-Max can hold machined tolerances to +/- .0005” (0,0127 mm) before plating. Typical manufactured tolerances are published in our General Technical Specifications.

Does Mill-Max offer non-magnetic parts?

Yes. For non-magnetic applications we stock a .093” diameter specialty brass containing less than .05% ferromagnetic material, suitable for most non-magnetic requirements. The larger concern is usually the nickel barrier plating used on brass parts to prevent zinc migration: for these designs the nickel is replaced with a thicker copper under plating, typically finished with gold. See Introduction to Mill-Max Custom Capabilities for the other material substitutions we offer.

Can you make a custom spring or a custom contact clip?

Custom springs, yes. Where a standard spring will not give you the force or travel your application needs, we can produce a custom one roughly around 12 to 14 weeks. Stainless steel springs for elevated force, ruggedness or high temperature, and low-force springs to reduce mating force, are already available as standard options.

Custom contact clips are possible by special request, but the tooling involved often makes them cost prohibitive. Before going that route we will look at whether a standard clip covers the requirement, since our range spans a wide set of pin acceptance ranges. Ideally the clip you choose has a pin acceptance mid-range near the diameter of the mating pin. See The Contact Clip, the Heart of the Mill-Max Receptacle. For high-temperature requirements, beryllium nickel equivalents to the standard beryllium copper clips are already offered.

What materials does Mill-Max machine?

Mill-Max machines Brass Alloy 360, phosphor bronze, and tellurium copper. Contact clips are beryllium copper as standard, with beryllium nickel available for high-temperature requirements, and internal springs can be specified in stainless steel for elevated force, ruggedness, or temperature.

Can different technologies be combined in one custom connector?

Yes. We regularly mix and match, for example an SMT connector with thru-hole alignment pins for mechanical stability, spring-loaded pins of differing heights for first-mate last-break sequencing, or threaded inserts for fastening. Introduction to Mill-Max Custom Capabilities covers the mix-and-match options in detail, including recombining plungers and bodies within a single spring-loaded pin.

Does Mill-Max offer over-molding?

Press-fit or interference-fit is the standard mounting method for Mill-Max parts in injection-molded insulators and housings. We offer several pins and receptacles that customers have used successfully in over-molded applications, can provide custom pins and receptacles with features designed for over-molding, and in some cases can provide a complete over-molded solution.

Can custom parts be supplied on tape and reel?

Yes. Customers should confirm their pick and place machine has the proper nozzle first. Press-fit parts are typically poor candidates for tape and reel because of the press-fitting requirement, though newer high-end machines can be fitted with press-fit nozzles. A minimum of 1 reel is required, and parts per reel range from 200 up. Where a part is not already offered on tape, custom carrier tape requires a nominal tooling charge to produce a pocket that fits it. We will also recommend features that make tape and reel packaging possible if a high-volume order is likely to follow. See Carrier Tape Options for Mill-Max Discrete Pins and Receptacles.

Can a custom part replace a stamped and formed component?

Typically, yes: a custom solution can be created to emulate many stamped products. Precision-machined parts are the right answer when you need to solve inadequate electrical or mechanical performance in a stamped product. They are not the low-cost alternative to stamping.

Are custom parts available lead-free and RoHS compliant?

Most Mill-Max products are available in both RoHS compliant and non-compliant versions, and where a product is not compliant the plating choice is usually the reason. Machined laminate and high-temperature molded materials are compatible with RoHS soldering processes including wave soldering, pin-in-paste reflow, and surface-mount reflow.

On lead content specifically: the free-machining brass we turn contains lead, which is what allows the high-speed machining our parts depend on. That lead content is covered by RoHS exemption 6(c), which permits copper alloy containing up to 4% lead by weight, so parts machined from it are RoHS compliant under that exemption rather than being lead-free.

We are not able to offer fully lead-free brass in volume at this time. If your application requires it, contact us with your requirement and quantity so we can tell you where things stand, since the situation is being actively worked. Lead-free alloy options do exist for some parts, so it is worth asking about your specific requirement rather than assuming either way.

How do I start a custom design?

Fill out the custom part worksheet with your dimensions, materials, and quantities, or contact an applications engineer directly. If you are starting from a standard part, use the product finder and click Customize this Part on the product details page. Our US-based engineering team will review the design for manufacturing feasibility and respond with a proposal.