The quality of a cast bronze bushing is not determined by one “core technology” or by the casting machine alone. Material control, casting route, machining allowance and inspection all affect whether the finished part meets the drawing.
JED manufactures custom bronze bushing castings to customer drawings. Each production and inspection plan is reviewed for the specific alloy, size, geometry and project requirements.
Casting Routes Used for Bronze Bushing Blanks
JED uses three main routes to produce bronze bushing blanks:
- Cantilever centrifugal casting
- Roller-supported centrifugal casting
- Vertical permanent-mold casting
Centrifugal casting is generally suited to cylindrical, sleeve-shaped and ring-shaped parts. Molten alloy is introduced into a rotating mold and solidifies under centrifugal force. The equipment arrangement is selected according to the component and production plan.
Vertical permanent-mold casting provides another route for suitable geometries. The final method is confirmed after the drawing, alloy, dimensions, quantity and technical requirements have been reviewed.
JED also operates horizontal continuous-casting equipment for bronze tubes and hollow products; it is not presented here as a direct bronze bushing casting route. See also how bronze bushings are cast.
How Quality Is Controlled Before and During Casting
Quality control begins before molten metal enters the mold. Incoming materials are inspected, and the alloy composition is checked against the order and applicable material standard. Composition is controlled during production to support traceability.
The melt and casting plan depends on the alloy, casting method, section thickness and geometry. Applicable melt-treatment practices may include dross removal, filtration, deoxidation or degassing. The necessary method varies by alloy and project.
Alloy-specific additives, temperatures, sequences and other internal parameters remain controlled manufacturing procedures. For buyers, the material grade, inspection plan and required records should be agreed before production.
Melt condition, pouring, mold preparation, metal quantity and solidification are controlled according to the approved route. For centrifugal castings, rotation and metal distribution must suit the part dimensions. One setting cannot simply be copied to a different alloy, diameter or wall thickness.
How Porosity, Inclusions and Shrinkage Are Evaluated
Porosity, inclusions and shrinkage are different conditions, not one general “pore problem.”
- Porosity or pinholes: small voids associated with gas during solidification.
- Inclusions: non-metallic material or foreign matter trapped in the casting.
- Shrinkage cavities: voids related to volume change during solidification.
Causes may involve the alloy, melt condition, mold, pouring, section changes or solidification. One action—such as raising the temperature—cannot be presented as the solution to every defect.
Inspection follows the drawing, applicable standard and agreed acceptance criteria. Visual inspection identifies visible surface conditions. Penetrant testing (PT) can reveal surface-breaking indications; ultrasonic testing (UT) may be arranged for suitable parts when internal examination is required. Applicability and acceptance criteria must be confirmed for the specific component.
Indications are evaluated against the confirmed requirements. A casting is released only after required inspections are complete and the specified criteria are met.
How Machining Allowance Is Determined
A bronze bushing blank needs sufficient material to machine the final diameters, end faces and functional features to the required tolerances and surface finish.
There is no universal rule that a blank should be three times the finished wall thickness or that two-thirds must be removed. Allowance depends on:
- Casting method and alloy
- Overall diameter, length and wall thickness
- Flanges, steps, grooves and section changes
- Expected as-cast dimensional variation
- Final tolerances and surface-finish requirements
- Machining datum, clamping and equipment access
- Inspection requirements
Too little allowance may prevent the final geometry from being achieved; excessive allowance increases metal use and machining time. Oversized parts also require review of the complete geometry and estimated weight. JED’s completed large bronze bushing projects show why diameter alone does not determine feasibility.
Inspection Reports and Three-Year Material Traceability
JED’s quality control includes incoming material inspection, composition control, dimensional inspection, defect control and final inspection. Depending on the order, the scope can also include:
- Chemical-composition testing
- Hardness testing
- Penetrant testing (PT)
- Ultrasonic testing (UT)
- Coordinate measuring machine (CMM) inspection
CMM inspection can verify specified dimensions and geometric characteristics on machined parts. See JED’s page about coordinate measuring machine inspection.
Reports can be provided for inspections performed under the order. Retained material samples are kept for three years to support traceability. Required reports, acceptance standards and document formats should be confirmed before production.
Discuss Your Requirements with a Bronze Bushing Manufacturer
JED manufactures custom cast bronze bushings from customer drawings and project data. Send the alloy or material standard, dimensions, tolerances, surface finish, quantity and inspection requirements. If the drawing is incomplete, also identify the application and operating conditions.
Contact JEDBUSHING to discuss the casting route, machining feasibility, inspection scope and documentation required for your project.