Counterbored Graphite Flange Bushings for CNC Tool-Changer Arms

CNC tool changer arm flange bushings guide a swing-arm pivot where the mechanism drawing specifies a sliding sleeve and bolted flange. MPKZ/OFP03-style graphite bushings provide a counterbored mounting interface for the specified screw heads. The component is separate from the spindle bearings, tool-grip mechanism and positioning drive.

Graphite-plugged flanged copper-alloy sleeve with cylindrical counterbored screw pockets — Existing BONIU product image reused as a construction example. It is not a photograph of this application or proof of an alloy grade. The approved drawing defines the supplied part.

Review the swing-arm pivot together with the tool-mass offset

The tool mass and arm offset create reactions that change during acceleration and deceleration. Dwell at transfer positions and repeated direction changes differ from continuous rotation. Required tool-transfer accuracy also depends on the complete pivot, drive, locking and structural arrangement, not the bushing alone.

Start with the matching BONIU product construction. Send the assembly section as well as the individual bearing drawing so that the working contact, locating surfaces and installation access can be reviewed together.

Dimensions and operating data for quotation

Review item	Required information
Arm duty	Tool masses, centre-of-gravity offsets, swing angle, acceleration/deceleration and cycle rate.
Pivot interfaces	Shaft and housing dimensions, bearing length, flange thickness, radial/axial clearance and alignment.
Screw pockets	Counterbore diameter/depth, through holes, socket-head dimensions, tool access and residual flange section.
Purchase specification	Drawing revision, quantity, units, exact material or composite specification, finish, inspection-document requirements and delivery destination.

Selection boundaries and installation

Confirm the locating diameter before tightening the fixing screws. Seat each screw head on its intended flat counterbore shoulder without bottoming on an incompatible radius. Check assembled movement, adjacent clearances and the approved lubrication arrangement. Keep chips and coolant from entering the sliding interface as required by the machine design.

Material and replacement approval

For copper-alloy parts, state the exact standard and grade required by the design. JDB/500# and geometry codes do not establish chemical composition. Do not treat different national alloy designations as interchangeable without checking their specifications. Product colour and a reused image cannot confirm material. Required documentation, dimensions and manufacturing scope are reviewed with the quotation.

Agree the material, counterface, operating clearance and acceptance criteria before approving a replacement. Include any required dimensional inspection, material documentation or sample review with the RFQ so it can be addressed in the quotation.

Purchasing questions

Can this bearing guarantee tool-change positioning accuracy?

No. Specify allowable pivot play and review it with the drive, lock and structural deflection.

Can a deeper counterbore be machined during assembly?

Only with an approved revision, since material removal changes the flange section and may affect graphite locations.

Is it a spindle bearing replacement?

No. This application is a swing-arm pivot with the specified sliding construction, not a high-speed spindle bearing.

Can the original product image be used to approve this application?

No. It illustrates the bearing structure. Use the approved part and assembly drawings to confirm dimensions, material, clearance and duty.

Request an application-specific quotation

Send your drawing and the checklist above through the BONIU enquiry page. Identify any proposed substitution explicitly so it can be reviewed before order confirmation.