Flush Mount Inductive Proximity Sensor — Shielded, M8 to M30, OEM China Factory
SEGMENsensor flush mount (shielded) inductive proximity sensors can be installed flush with, or recessed within, a metal mounting bracket — no interference from surrounding metal. The ferrite shielding ring confines the electromagnetic sensing field to the front face only, allowing true embedded installation in machine frames, fixtures, and conveyor beds. 6.5 mm, M8, M12, M18, M30 sizes. NPN or PNP, NO/NC. CE and RoHS certified. OEM from Shenzhen since 2019, OEM volume supply.
Flush-MountableMetal-Panel InstallationEmbeddable in MetalOEM volume supply
Key facts
A SEGMENsensor flush mount inductive proximity sensor is a shielded sensor whose ferrite ring confines the sensing field to the front face, so it can be installed flush with or recessed into a metal bracket without false triggering. It is available in 6.5 mm, M8, M12, M18 and M30 barrels (SGI-GP flush part numbers); square SGI-GPQ part numbers are on request.
Rated sensing distance on mild steel is 1–4 mm (6.5 mm and M8), 2–8 mm (M12), 5–15 mm (M18) and 10–25 mm (M30).
Outputs are NPN or PNP, NO or NC, on 10–30 V DC supply; DC 2-wire (10–60 V DC) and AC/DC (20–250 V AC/DC, M12 to M30) are also available.
Output current, switching frequency, protection class and operating temperature are given on the datasheet sent with the quotation.
Housings are nickel-plated brass, with stainless steel on 6.5 mm and M8 and PTFE-coated brass on some M8 and M12 models.
Qualification samples are 1–5 pcs, and the sensors carry CE and RoHS compliance.
Last updated · SEGMENsensor Engineering Team
Watch: how an inductive proximity sensor works
How an Inductive Proximity Sensor WorksOne-minute animation: oscillator and coil, eddy currents in a metal target, the drop in oscillation amplitude that switches the output, and what sets the switching distance Sn.
How does an inductive sensor detect metal without contact? Inside the sensor, an oscillator drives a coil wound on a ferrite core. It creates a high-frequency magnetic field in front of the sensing face. When a metal target enters the field, eddy currents are induced in the metal. They draw energy from the field, and the oscillation amplitude drops. When the amplitude falls below the threshold, the trigger switches the output, and the LED lights up. The switching distance, Sn, depends on the sensor size and the target material. Mild steel gives the full rated distance. SEGMENsensor inductive sensors: M8 to M30, Sn 1–25 mm. Learn more at segmensensor.com.
What is a Flush Mount Inductive Proximity Sensor?
A flush mount (also called shielded or embeddable) inductive proximity sensor has a ferrite ring shield surrounding the sensing coil. This shield concentrates the electromagnetic field to the face of the sensor only, preventing side interference from metal brackets, frames, or machine beds. The sensor can be installed with its tip flush with or recessed below the surface of a metal mounting panel — unlike non-flush (unshielded) sensors, which require a metal-free zone around the body. Flush mount sensors trade slightly shorter sensing distance (approximately 60% of unshielded distance) for the ability to be deeply embedded in metal machine structures.
Specifications
Flush Mount Inductive Proximity Sensor — Full Specification Table
All standard shielded (flush-mountable) configurations. NPN or PNP, NO or NC specified at order. Square SGI-GPQ part numbers on request.
Per part number, given on the datasheet sent with the quotation
Cable
2 m cable (other lengths on request)
Connector
M12 connector; M8 connector and M8 / M12 pigtail on smaller sizes (fixed by the part number)
Thread
M8×1 / M12×1 / M18×1 / M30×1.5
Operating Temperature
Per part number, given on the datasheet sent with the quotation
Samples
Samples 1–5 pcs for qualification; volume per project
Lead Time
Confirmed with the quotation (standard production); samples 1–5 pcs in 5–7 days; custom OEM confirmed at order
Certifications
CE, RoHS
Download the inductive proximity sensor datasheet (PDF)
One-page datasheet with all sizes, sensing distances, output options, supply voltage, connection types, housing materials, temperature limits, IP rating, dimensions and the ordering code. No registration required.
Flush Mount vs. Semi-Flush vs. Non-Flush — How to Choose
Match the correct installation type to your mounting structure. Shielded sensors are required for any metal panel installation.
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Fully Flush Recessed in metal panel
Sensor end face is level with the metal mounting surface
Common in machine tool worktables and fixture positioning holes
Used in AGV guide rail slots and CNC pallet changer pockets
Install: thread sensor into M8/M12/M18/M30 tapped hole until face is flush
→ Use shielded (flush-mount) sensor only
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Semi-Flush Protrudes 1–3 mm from panel
Sensor tip protrudes 1–3 mm above the metal surface
Slightly shorter sensing distance than non-flush variant
Suitable for metal frame side-face mounting with mechanical protection
Shielded sensor required — no metal-free zone needed around body
→ Shielded sensor (flush type) preferred
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Non-Flush Plastic or non-metal bracket
Unshielded sensor — maximum sensing distance
Requires metal-free zone equal to sensor diameter around body
Ideal for plastic brackets, rubber pads, non-metal mounting surfaces
Do not use in metal panels — will cause false triggering
→ Unshielded (non-flush) sensor — see proximity-sensor.html
Need help choosing flush vs. non-flush for your machine design?
Send us your CAD drawing or describe your mounting panel material and thickness — our engineers will specify the correct shielded sensor model within 24 hours.
8 Industrial Applications for Flush Mount Inductive Sensors
Shielded proximity sensors are the standard solution wherever sensors must be embedded into metal machine structures without protrusion or false-trigger risk.
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Machine Tool Fixtures
Workpiece presence detection in metal fixture jaws — flush installation eliminates chip damage and allows deep recess in steel fixture bodies.
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Conveyor Bed Detection
Metal part detection through conveyor bed sheet metal — sensor embedded in stainless conveyor tray with no protrusion hazard to passing workpieces.
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AGV / AMR Guide Rails
Embedded in aluminum guide rail slots for reliable vehicle positioning — flush sensor profile prevents mechanical interference with AGV chassis.
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Robotic Weld Cells
Flush mount in steel weld fixtures for workpiece presence confirmation — use ceramic-face variant for resistance to weld spatter in spot welding environments.
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Injection Mold Parting
Mold parting detection in metal tool steel — requires true flush embeddable sensor as non-flush variants cannot be used in steel mold frames.
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CNC Pallet Changer
Pallet position detection in recessed steel pockets on machining center tables — flush M18 sensors in blind-bore mounting holes confirm pallet seating.
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Hydraulic Valve Blocks
Manifold-embedded spool position detection in hydraulic valve bodies — M8 or M12 shielded sensors recessed into ported manifold bores.
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Semiconductor FOUP
Wafer carrier detection in stainless steel equipment frames — M8 stainless steel flush sensor (SGI-GP08S or SGI-FM08S); cleanroom suitability is confirmed with the quotation.
Wiring
Flush Mount Inductive Sensor Wiring — NPN, PNP, M12 Pinout
All SEGMENsensor flush mount proximity sensors follow IEC/EN 60947-5-2 standard wiring. 3-wire DC connection to PLC digital input card.
01
NPN-NO Wiring
Brown wire = +V (10–30V DC supply) Blue wire = 0V (common / negative) Black wire = Output → PLC digital input (sinking)
When target enters sensing range: output pulls LOW (0V). PLC detects logic LOW = target present. Most common in Asia/China PLC installations.
02
PNP-NO Wiring
Brown wire = +V (10–30V DC supply) Blue wire = 0V (common / negative) Black wire = Output → PLC digital input (sourcing)
When target enters sensing range: output pulls HIGH (+V). PLC detects logic HIGH = target present. Standard in European PLC systems.
03
M12 Connector Pinout
IEC/EN 60947-5-2 standard A-coded M12×1 4-pin:
Pin 1 = Brown (+V supply) Pin 2 = White (second output or shield) Pin 3 = Blue (0V / common) Pin 4 = Black (switching output)
Mating M12 cable connectors and panel-mount sockets available in the same catalog.
Flush vs. Non-Flush Comparison
Flush Mount (Shielded) vs. Non-Flush (Unshielded) — Technical Comparison
Choose the correct type based on your mounting panel material and required sensing distance.
Parameter
Flush Mount (Shielded)
Non-Flush (Unshielded)
Metal panel installation
Yes — no metal-free zone needed
No — requires metal-free zone around body
Sensing distance (M18)
5 / 8 / 12 / 15 mm (Sn, mild steel)
8 / 16 / 20 / 23 mm (Sn, mild steel)
Ferrite shield ring
Yes — confines field to front face
No — radial field from body sides
Mounting in steel frame
Fully supported
False triggers — not suitable
Mounting on plastic bracket
Works (shorter sensing distance)
Preferred (maximum sensing distance)
Weld cell use
Supported — SGI-WR weld-field immune series
Less common in weld cells
Samples from SEGMENsensor
Samples 1–5 pcs for qualification; volume per project
1–5 pcs, 5–7 working days
FAQ
Flush Mount Inductive Proximity Sensor — Frequently Asked Questions
Technical and sourcing questions answered by SEGMENsensor application engineers. Planning an OEM program? Read the inductive proximity sensor OEM guide.
What is the difference between flush mount and non-flush inductive sensors?
Flush mount (shielded) sensors have a ferrite ring that confines the sensing field to the front face, allowing installation in metal panels with no side interference. Sensing distance is shorter: M18 flush = 8 mm (vs 16 mm unshielded). Non-flush (unshielded) sensors project the field radially from the body, giving longer sensing distance but requiring a metal-free zone (typically equal to sensor diameter) around the body to prevent false triggering from the mounting hardware. Use flush mount when embedding in metal structures. Use non-flush when mounting on plastic brackets where maximum sensing distance is needed.
What is the sensing distance reduction for non-steel metals with flush mount sensors?
Rated sensing distance (Sn) applies to mild steel (Fe360). For other metals such as aluminum, brass, copper or stainless steel, multiply Sn by the correction factor given on the datasheet sent with the quotation. For consistent detection of non-ferrous targets, use the unshielded version to maximize sensing distance, specify the SGI-FM all-metal family, or test with the actual target material before finalizing your mounting design.
Can flush mount inductive sensors be installed in stainless steel panels?
Yes — this is one of the main advantages of shielded (flush mount) sensors. Stainless steel has lower magnetic permeability than mild steel, which reduces the shielding effect slightly, but shielded sensors are still installable in stainless steel panels. Sensing distance on a stainless steel target from within a stainless steel panel is reduced compared with the rated Sn. For stainless steel housing sensors in stainless steel panels with stainless steel targets (common in food/pharma), use the stainless steel SGI-FM all-metal family and verify detection distance during fixture design. SEGMENsensor engineering can advise on specific sensor-target-panel combinations.
What is a weld-immune flush mount sensor?
Weld-immune flush mount sensors are shielded inductive sensors with a ceramic (Al₂O₃) front face that resists weld spatter adhesion and withstands the electromagnetic pulses from MIG, TIG, and resistance spot welding. Standard plastic (PBT) front faces degrade quickly in weld spatter environments — spatter adheres and eventually blocks the sensing face. The ceramic face allows spatter to bead off, and internal electronics filter welding current pulses. The flush mount version of weld-immune sensors is used in resistance spot welding gun position detection and automotive body stamping transfer fixture workpiece sensing.
What M12 connector pinout should I use for flush mount proximity sensors?
SEGMENsensor uses IEC/EN 60947-5-2 standard M12×1 4-pin A-coded connector pinout: Pin 1 = Brown (+Vs, 10–30V DC positive supply); Pin 2 = White (second output or shield, if applicable); Pin 3 = Blue (0V, negative/common); Pin 4 = Black (switching output). For 3-wire NPN-NO: connect Pins 1, 3, 4 — Pin 4 output switches to 0V when target present. For 3-wire PNP-NO: connect Pins 1, 3, 4 — Pin 4 output switches to +Vs when target present. Mating M12 cable connectors and panel-mount sockets available in the same catalog.
Is there a minimum mounting distance between two flush mount sensors?
Yes. Two identical flush mount sensors mounted side by side can experience mutual interference (sympathetic oscillation), causing false or unstable outputs. Minimum center-to-center distance: 2× sensor diameter for same-frequency sensors (e.g., two M18 sensors: minimum 36 mm center-to-center). For sensors of different sizes, use the larger sensor's diameter as the reference. This limitation can be eliminated by using sensors with different oscillator frequencies (ask SEGMENsensor for frequency-matched pairs) or by using sensors with anti-interference mode (mutual interference suppression circuit).
Can flush mount sensors detect objects through thin metal sheets?
Yes, in some configurations. A flush mount sensor can detect a metal target on the opposite side of a thin non-ferrous sheet (e.g., 1–2 mm aluminum plate) — the sheet is transparent to the electromagnetic field. However, a ferrous (steel) sheet will shield the field significantly. The practical rule: if the intervening material is non-ferrous and thinner than 0.5× Sn, the sensor can "see through" it. This principle is used in conveyor bed metal part detection — the sensor is embedded in a stainless steel conveyor tray and detects steel parts passing above. Always prototype and test for your specific material and thickness combination.
What is the OEM MOQ and lead time for flush mount inductive sensors from a China factory?
Qualification samples are 1–5 pcs for standard flush mount (shielded) inductive proximity sensors (SGI-GP flush part numbers: 6.5 mm, M8, M12, M18, M30, NPN/PNP, NO/NC, 2 m cable or M12 connector). Samples of 1–5 pcs ship in 5–7 days for testing. Standard configurations: production lead time confirmed with the quotation. Custom options (cable length, cable material, housing material, OEM label; SGI-HT high-temperature and SGI-WR weld-field immune series): production lead time confirmed with the quotation. CE and RoHS declaration of conformity with every order. Factory: SEGMEN (Shenzhen) Industrial Development Co., Ltd., Registration No. 91440300MAEUXXQU04, Shenzhen, Guangdong, China.
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