Slotted Flexible Coupling Adapter Sleeve 0.01mm Bore Fit Single Setup Turning for Servo Motor Shaft Connection

Product Overview

This slotted flexible coupling adapter sleeve connects a servo motor shaft to a lead screw, gearbox input or encoder shaft while absorbing parallel, angular and axial misalignment that a rigid coupling would pass straight into the bearings. The body is turned and the helical slot is milled in the same clamping, so the two bores, the slot and the set screw holes all share one centre line. That is the difference between a coupling that runs quietly at 3,000 rpm and one that transmits a once-per-revolution vibration into the motor.

The sleeve is made from 303, 304, 316L or 17-4PH stainless steel. The bore is reamed to H7 and held within 0.01 mm fit control, the clamping diameter runs within 0.01 mm TIR, and the slot width is held to +/-0.03 mm so the torsional stiffness stays inside the range assumed by the drive calculation. Radial set screw holes are drilled, tapped and deburred from the inside so no chip or burr can score the shaft during assembly.

Production Process — How the Sleeve Is Made

1. Drawing and DFM review. We check bore fit, slot width, wall thickness under the slot, set screw depth and the torque the sleeve must carry, then return a marked drawing and a quotation within one working day.
2. Material verification. Bar stock is checked against the mill certificate for grade and condition; 17-4PH is verified for heat-treat condition before machining.
3. Sawing and stress relief. Bars are cut oversize and stress relieved where the slot removes a large share of the section, so the bore does not close after slotting.
4. Turning of bores and diameters. Both bores, the stepped outside diameters, the clamping faces and the chamfers are turned in one programme, with the second bore referenced to the first to keep concentricity at 0.01 mm.
5. Slot milling on the same machine. The part is not released: the helical or straight slot is milled with a small end mill in multiple depth passes, which controls cutter deflection and keeps the slot wall square.
6. Cross drilling and tapping. Set screw holes are drilled, tapped and chamfered, then deburred from the bore side so the shaft slides in without catching.
7. Heat treatment and passivation. 17-4PH parts are aged to H900 where high torque is required; all stainless parts are passivated to restore the chromium oxide layer after machining.
8. Final inspection and packing. Bore size with a bore gauge or air gauge, concentricity and runout on a fixture, slot width by pin gauge, then CMM sampling and a first article report with the batch.

Precision and Inspection

Why the Slot Geometry Matters

The slot is the functional heart of a flexible coupling, and it is also the feature most often compromised by splitting the job across two suppliers. A slot that is too wide lowers torsional stiffness and lets the drive oscillate; a slot that is too narrow or has a sharp internal corner starts a fatigue crack at the radius. We mill the slot with a defined corner radius, keep the ligament thickness uniform along its length, and check the width with a pin gauge rather than trusting the cutter nominal. For high-speed applications we can also balance the finished sleeve to G6.3, which keeps vibration low when the coupling runs above 6,000 rpm.

Non-Standard Customization

Nothing on this page is a fixed catalogue size. We build to your drawing and can change the bore combination, the outside diameter, the overall length, the slot pattern, the number and position of set screw holes, the material grade, the heat treatment and the surface finish. One piece is a normal order with no tooling charge and no setup fee, and the prototype is machined with the same programme and inspection plan used for the batch. Where a design would be difficult to machine, our engineer returns a DFM note with a practical alternative and waits for written approval before any metal is cut.

Confidentiality

• NDA before files. A mutual non-disclosure agreement is signed before drawings, models or samples are released, covering geometry, volume, end use and customer identity.
• No reference use. Confidential couplings are never shown as samples, catalogue items, website photos or trade show parts, and photographs need written release.
• Separated production. Sensitive jobs run in a designated cell with named operators; programmes and fixtures are filed under a project code rather than the customer name.
• Controlled data. Files stay on an access-controlled server; heat treatment and passivation partners receive the process specification only, never the assembly drawing.

Company Introduction

Dongguan Changxinda Precision Technology Co., Ltd has produced custom machined parts since 2008. The plant operates four-axis and five-axis machining centres, turn-mill combined lathes, CNC lathes and milling machines, with 90 to 102 employees and an ISO 9001:2015 quality system. We serve more than 200 customers, export 50 to 60 percent of our output and record annual sales between USD 10 million and 20 million. Three working habits hold the service together: a named engineer on every custom project, a first article report with every batch, and a delivery date confirmed before the order is accepted.

Delivery Stability

• Dates confirmed in writing. Prototypes in 3 to 7 working days, batch orders in 10 to 20 working days after drawing approval.
• Repeat orders skip setup. Programmes, fixtures and inspection plans stay on file, so the second order starts in production rather than in programming.
• Reserved capacity. Blanket orders are booked into fixed monthly slots, keeping the same part arriving in the same week each month.
• Early warning. If material, heat treatment or passivation threatens the date, you are told before the date is missed, with a partial shipment or air-freight split offered.
• Dispatch evidence. Production photos, inspection report and packing list before shipment, tracking number on the day the goods leave.

Ten Industries We Machine For

• ✅ Consumer Electronics: phone, tablet and laptop housings, heat sinks, camera brackets, VR/AR headset structural parts, smart wearable shells
• ✅ Automation & Industrial Equipment: automation fixtures, jigs, module frames, transmission sliders, motor mounts, sensor housings, conveyor line parts
• ✅ Semiconductor & Vacuum Equipment: vacuum chambers, vacuum fittings, precision equipment bases, thermal isolation and insulation parts, inspection fixtures
• ✅ Medical Devices: surgical instrument bases, diagnostic instrument housings, endoscope components, aesthetic device structural parts (medical-grade aluminum and stainless steel)
• ✅ Automotive: new energy motor housings, battery end plates, sensor brackets, lamp structural parts, tuning parts, hydraulic valve blocks
• ✅ Aerospace & UAV: aircraft structural parts, drone frames, landing gear parts, avionics instrument housings (lightweight precision parts)
• ✅ Optics & Photonics: optical lens barrels, lens mounts, light source heat sinks, camera module brackets, inspection optical benches
• ✅ Communications: 5G heat dissipation cavities, filter parts, signal adapter structural parts, telecom equipment housings
• ✅ Robotics: robot arm joint parts, robot bases, reducer housings, AGV structural parts
• ✅ Instrumentation: test equipment housings, precision gauge bases, flow meter parts, laboratory equipment accessories

Packing and Export

Each sleeve is bagged with a desiccant sachet, separated by EPE foam so polished bores cannot knock against each other, and packed in a five-layer export carton marked with part number, quantity and batch code. Sea freight is palletised on fumigation-free plywood with strapping and stretch film; air freight uses a reinforced carton with edge protectors. Neutral packing is available for distributors selling under their own brand.

FAQ

Q: Can you hold 0.01 mm fit on both bores in one part?
A: Yes. Both bores are turned in the same programme without releasing the part, and the second bore is referenced to the first. We verify with a bore gauge and check concentricity on a fixture before the batch is released.

Q: What is the minimum order?
A: One piece. There is no tooling charge and no setup fee, and the prototype follows the same process as production.

Q: Can you sign an NDA before I send the drawing?
A: Yes, and we prefer to. Confidential parts are excluded from samples, photos and case studies by default.

Q: Which stainless grade should I choose?
A: 303 for general drive use and good machinability, 304 where corrosion resistance matters, 316L for marine or chemical exposure, and 17-4PH when torque is high and the part can be aged to H900.

Q: Can you balance the coupling?
A: Yes. Dynamic balancing to G6.3 is available for high-speed servo applications, and the balance report can ship with the batch.

Send the drawing with bore sizes, torque and maximum speed, and we will return a DFM review, a quotation and a confirmed delivery date within one working day.