High Precise Machined End Plate For Motor Case

Oil Weep, Hot Bearings, And The Plate At The End Of The Case

A puddle under a gearbox is almost always blamed on the gasket. More often it is the flatness of the cover plate. The end plate closes the housing, positions the output bearing, sets shaft end-float, and carries the mounting flange - four jobs on one part, so a few hundredths of a millimetre of error surfaces as a leak or a burnt bearing.

A plate 0.05 mm out of flat never compresses its gasket evenly, so the joint weeps once the case reaches running temperature. A bore machined off-centre preloads the bearing, and the bearing fails early while the rest of the motor is still sound.

This plate is machined from 6061-T6 aluminum on a 3-axis CNC platform, held to ±0.01 mm on load-bearing faces and bores, and honed where the bearing or shaft seal sits. Every unit runs to your drawing or supplied sample - in SXFD brand or under your own label, with alloy, finish, marking, and packing fixed before production.

What This Plate Is Built To Do

• Machined from 6061-T6 aluminum as standard - machines cleanly, resists corrosion, welds without special procedure.
• 3-axis CNC machining for the mounting face, bolt pattern, steps, and pockets - the plate is approachable from one direction, so 3-axis is the honest fit rather than an over-specified platform.
• ±0.01 mm on critical call-outs - face flatness, bore position, bolt-hole pitch.
• Honed inner bore (ID), so the bearing or seal seat meets controlled roundness and roughness instead of the helical mark a boring bar leaves.
• Hard anodized surface against oil, coolant spray, and washdown.
• Outline to your drawing - square, rectangular, round, or any footprint the casing requires.
• Samples available before a production order is committed; export packing in plywood cases.
• Lead time 30–45 days after drawing confirmation; EXW, FOB, or CIF by sea, air, train, or express.

Technical Data

Standard specification for this end-plate line. Alloy, finish, and dimensional call-outs are confirmed against your drawing at quotation.

Which Aluminum, And When To Choose Something Else

6061-T6 is standard here and right for most motor-casing work: tensile strength around 310 MPa, yield around 276 MPa, density 2.70 g/cm³. It holds a machined edge without the burrs softer tempers raise, and it anodizes predictably - which matters when the plate is the visible end of a housing.

Where the drawing points elsewhere, the same programme runs on 6082-T6 (the European near-equivalent, common on EU OEM drawings), 7075-T6 (around 570 MPa tensile, where the plate also carries load or must stay thin), or 2024-T4 (higher strength again, needing a protective anodize). Mill certificates are issued against the production batch on request.

Milling The Face, Honing The Bore

Two operations decide how this plate performs, and they are not the same one.

The face is milled, then checked for flatness: it is the datum the rest of the plate is measured from, and the surface the gasket seals against. The bolt pattern is drilled and, where specified, reamed for a dowel-pin register so the plate locates on the housing rather than on bolt clearance.

The bore is a separate story. Boring leaves a single-point tool mark spiralling down the wall, and a bearing pressed into that wall inherits the spiral as a contact pattern. Honing crosses it with a rotating, oscillating abrasive, tightening roundness and bringing the surface to a controlled roughness - typically Ra 0.4–0.8 µm on a bearing seat - so the bearing contacts around the full circumference instead of seating on a high spot and working loose. Where an angled port or undercut is out of reach in one orientation, the job moves to a 4th- or 5-axis platform rather than compromising the feature.

How ±0.01 mm Is Measured And Held

Tolerances are only worth what the inspection behind them is worth, so each batch is checked at three points. First-article inspection runs on a coordinate measuring machine (CMM) against the full drawing, including GD&T call-outs. Flatness is confirmed on a granite surface plate and cross-checked on the CMM; bore roundness and size are verified with bore micrometers, plug gauges, or an air gauge where specified.

In-process checks run at the machining checkpoints, and final sampling runs before packing with a report per batch - critical dimensions, surface roughness (Ra), and coating thickness on the anodized layer. Independent inspection through SGS, BV, or TUV can be arranged at the buyer's cost.

Motors, Pumps, And Gearboxes That Use This Plate

• Gear motors and speed reducers - the plate locates the output bearing and sets end-float.
• AC and DC motor housings - end covers carrying the shaft seal and mounting flange.
• Pump and hydraulic motor casings - end covers holding a seal face flat under pressure cycling.
• Servo and stepper motor flanges - where bolt pitch and bore concentricity set coupling alignment.
• Blower and fan housings - plates under continuous vibration and dust.
• Custom gearboxes, prototype drives, and legacy replacement - low-volume runs where a catalog cover will not do.

Drawing Changes And Private-Label Runs

• Geometry - outline, thickness, bolt pattern, bore diameter and depth, steps, pockets, dowel-pin positions.
• Material - 6061-T6 standard; 6082, 7075, 2024, or cast A356 on request.
• Surface - hard anodized Type III to MIL-A-8625 as standard; clear, dyed colours, or machined-only finish.
• Marking - laser-etched part numbers, batch codes, brand logos, or compliance text.
• Tolerance - ±0.01 mm on critical features; tighter call-outs reviewed against inspection capability.
• Packing - individual wrapping, kit assembly with gaskets and fasteners, retail box, or bulk packs.

Sample lead time is 10–15 days after drawing confirmation, shipped by express so the fit can be approved before tooling is committed.

Checks At Incoming, In-Process, And Final

Material arrives against a mill certificate and is verified for grade before it reaches a machine. In-process inspection runs at the machining checkpoints, with first-article approval on every new programme. Final inspection samples the batch against the drawing before packing, checking coating thickness and appearance on the anodized parts. Every batch is traceable from batch number to machine, operator, and inspector. Parts that fail are quarantined and reworked where possible, or replaced before the shipment closes.

Crating, Lead Time, And Freight

Plates are wrapped to protect the machined faces and the anodized finish, packed in lots, and shipped in plywood cases sized for container export. Documentation per shipment includes the commercial invoice, packing list, material certificate where requested, and inspection report. Lead time is 30–45 days from confirmed order and approved sample, depending on batch size and anodizing queue. Production volumes ship by sea; samples and urgent orders by air or express. Incoterms are EXW, FOB, or CIF as agreed.

The Purchase Order, Step By Step

• Drawing - a 2D drawing, a 3D model, or a physical sample.
• Evaluating - manufacturability, alloy, and any feature needing a different machine setup.
• Quoting - a quotation covering alloy, finish, tolerance budget, tooling notes, and lead time.
• Sampling - sample units machined against the approved drawing.
• Testing - you assemble the samples and check fit, seal, and shaft rotation.
• Feedback - changes to fit, finish, or tolerance folded into the production programme.
• Mass production - the released drawing goes to the shop.
• Inspection - in-process and final checks against the inspection plan.
• Packing and shipping - parts crated, documented, and handed to freight on the agreed incoterm.

Terms Of Payment

T/T, Western Union, PayPal, and L/C are all accepted - typically a deposit against the order with the balance settled against the shipping documents.

ISO 9001:2015 Certified

 

SXFD is certified by China Quality Certification Centre Registration to be ISO 9001:2015 compliant. This means that our company has developed, implemented and maintains a quality management system that conforms to the requirements of ISO 9001:2015. Those requirements are as follows:We demonstrate our ability to consistently provide products and services that meet customer and applicable statutory and regulatory requirements.We aim to enhance customer satisfaction through the effective application of the system, including processes for improvement of the system and the assurance of the conformity to customer and applicable statutory and regulatory requirements.SXFD applies its quality management system to our manufacturing and distribution processes, ensuring that customers can rely on consistent quality and care.

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FAQ

Send Us Your Drawing And Sample

Your drawing (STEP / DWG / PDF) or a physical sample
Annual volume and lot size
Alloy, finish, and colour preference
Target tolerance on the bore and mounting face
Incoterm and destination port
We will reply with a quotation, a lead-time estimate, and a sample plan within two working days.

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