Custom and OEM Proximity Sensors: Specials, Private Label and Volume

Most machine builders take the catalogue part and design around it. An extra junction box because the cable was too short, a machined adapter because the thread was wrong, a bracket because the sensor would not sit flush. Each of those is small. Multiplied by every machine you ship, they stop being small.

If you build in volume, a sensor made to your specification usually costs less than the workarounds it removes. We manufacture in Mumbai, which means the production line is the same place as the engineering, and a special is a scheduling question rather than an international negotiation.

What can be changed

Cable length, exactly. The most requested change and the one with the clearest payback. A sensor supplied with the run you actually need removes a junction box, a gland and a labour operation from every machine.

Connector type and pin assignment. M12 connectors are near universal in European machine building but the pin assignment is not. If your harness expects something specific, the sensor can be built to match rather than adapted afterwards.

Housing material and finish. Stainless for washdown and food duty, PTFE coating where weld spatter is the enemy, specific platings where the chemistry demands it.

Sensing distance and shielding. Where the mechanical arrangement is fixed and the standard range does not suit it, the coil and shielding can be specified to the gap you actually have rather than the other way round.

Thread and body length. Non-standard barrel lengths for brackets that already exist, so the machine does not have to change.

Output configuration. PNP or NPN, normally open or normally closed, and the short-circuit protection behaviour, set to what your input card expects.

Temperature and environmental rating built for the worst case your machine actually sees, rather than the catalogue assumption.

Private label

If you sell machines under your own name, the sensors inside can carry your marking rather than ours. Laser-marked part numbers to your own numbering scheme, your logo, and packaging that matches the rest of your spares programme.

The commercial reason is usually spares. A customer who needs a replacement sensor should be ordering it from you, with your part number on it, not working out who made it and buying direct. For an OEM with an installed base, that is a revenue stream rather than a vanity exercise.

What a special actually takes

Being straight about this, because it determines whether it is worth doing.

Volume. A special needs enough annual quantity to justify setting it up. One-offs and small batches are better served by a catalogue part, and we will say so rather than quote you something uneconomic.

A clear specification. The more precisely you can state what has to change and what must not, the faster it goes. A drawing of the mounting is worth more than a paragraph.

Lead time for the first article. The first batch takes longer than a repeat. Plan the first one against your build schedule rather than against a breakdown.

A sample and sign-off cycle. You should see and test the first article before the production run. Nobody benefits from discovering a misunderstanding at quantity.

When a special is worth it, and when it is not

Worth it: steady annual volume, an existing mechanical design you do not want to alter, a repeated assembly operation the special would remove, a spares channel you want to own, or an environment the catalogue range does not properly address.

Not worth it: low or uncertain volume, a design still in flux, or a requirement that an existing catalogue part already meets. On that last point, start with the standard D30C range. It covers M8 to M50 and 4 mm to 30 mm sensing in every output combination, and it solves most of what gets asked for as a special.

Replacing an imported special

A common starting point. A machine was designed around an imported sensor that is now on a long lead time, has been rationalised away, or costs more than it did. Send us the part number, a photograph of the installation and the function it performs, and we will tell you honestly whether a standard part covers it or whether it genuinely needs a special. Our guide to cross-referencing imported proximity switches covers the parameters that have to match.

Starting a special

Send us the application, the mechanical arrangement, what has to change from standard, your expected annual volume and the first delivery you need to hit. A drawing or a sample of the existing part answers most of it at once. We will come back with what is possible, what it needs, and whether a standard part would do the job better.