Custom Link Arm Manufacturer
Link Arm
Custom Link Arm Manufacturing FAQs
Can SIMIS manufacture link arms from customer drawings?
Yes. SIMIS provides drawing-based OEM manufacturing for metal link arms used in motion-control and load-transfer assemblies. We review 2D drawings or 3D CAD models, material specifications, connection geometry, expected loads, production quantity and inspection requirements before proposing a casting, forging, machining or fabricated manufacturing route.
Should a custom link arm be forged, cast or machined?
There is no single process suitable for every link arm. Closed-die forging may be evaluated for compact, repeatedly loaded arms where strength and fatigue behavior are critical. Ductile iron or steel casting may suit larger or more geometrically complex arms when validated for the application. CNC machining can create prototypes, lower-volume parts and the critical bores or joint surfaces of cast or forged blanks.
Which dimensions are most important on a link arm?
The center-to-center distance between attachment points, bore diameter and fit, parallelism or angular relationship of joint axes, mounting-face position, and clearances near the moving mechanism are often key. The drawing should define datums and geometric tolerances based on the assembly. Each component is evaluated against its actual load path and mating parts.
How do you evaluate fatigue and impact requirements?
Load direction, load spectrum, peak forces, impact conditions and target service life influence material, section thickness, fillet geometry, heat treatment and inspection planning. Where required, fatigue or proof-load testing must be specified and validated through an agreed test plan; manufacturing alone does not guarantee a particular fatigue life or safety certification.
What information is needed for a custom link arm quotation?
Please share drawings or CAD files, application details, material or performance requirements, bushing or pin specifications, critical tolerances, surface finish, annual or batch quantity, and any required inspection or testing standards. This allows us to assess tooling, machining, finishing and commercial feasibility.
OEM Link Arms Manufactured to Your Drawings
A link arm transfers force or constrains movement between two or more pivot points. Although many arms look simple, the accuracy of their attachment interfaces strongly affects assembly, motion and wear. SIMIS supports OEM enquiries for forged, cast and machined metal links used in machinery, vehicle suspensions, heavy equipment and articulated mechanisms.
The term link arm covers several different component designs. A suspension lateral link, a hydraulic mechanism link and an industrial connecting lever may share a pin-and-bore arrangement, but their loading, failure modes and production processes can differ substantially. Our manufacturing proposal therefore starts with the customer’s functional drawing—not with a one-size-fits-all list of manufacturing methods.
If your project specifically concerns a vehicle suspension wishbone, see our custom suspension control arm page; for steering linkage designs, see custom tie rod arm. This page focuses on the broader family of custom structural and articulating link arms.
Selecting the Manufacturing Process for a Link Arm
Process selection should account for the required material condition, section geometry, recurring loads, joint design, tooling investment and order quantity. Near-net-shape blanks often still require CNC machining of functional interfaces.
| Manufacturing route | Where it may be appropriate | Important engineering considerations |
|---|---|---|
| Closed-die forging | Repeatedly loaded steel or aluminum arms with a forgeable geometry and suitable production volume | Die parting and draft, grain flow, flash removal, tooling cost and post-forge heat treatment |
| Sand or shell-mold casting | Larger or complex ductile iron or steel links where casting is permitted by the component design | Section transitions, feeding, material properties, machining stock and inspection |
| Investment casting | Smaller intricate links or fittings when detail and material selection justify the process | Wall thickness, achievable as-cast features, tolerances and subsequent finishing |
| Machining from stock | Prototype or smaller-batch link arms, and geometries that can be cut economically from stock | Material waste, cutting accessibility, fixture design and machining time |
| Welded fabrication | Selected structural configurations requiring plates, tubes or separate bosses | Weld design, distortion control, appropriate procedure qualification and inspection |
For components with demanding tensile, bending or alternating loads, closed-die forging may be a candidate. For cast geometries, our sand casting and investment casting pages explain related manufacturing approaches. The final route remains subject to drawing and production feasibility review.
Material Options: Strength, Weight, Toughness and Corrosion
The material must suit the actual working load and environment. Material families listed here are engineering options for evaluation, not a claim that every grade is stocked, certified or interchangeable across processes.
| Material family | Typical selection considerations | Points to confirm |
|---|---|---|
| Alloy or carbon steel | Strength, impact tolerance, machinability and potential for specified heat treatment | Exact grade, mechanical property condition, hardness and inspection |
| Forging aluminum alloys | Lower mass for eligible lightweight link designs | Selected wrought/forging grade, temper, fatigue demands and corrosion environment |
| Ductile cast iron | Castability for selected complex sections and useful strength/ductility combinations | Casting grade, wall thickness, load validation and any impact-property requirement |
| Cast steel | Complex cast geometry combined with steel properties for suitable applications | Grade, heat treatment, soundness criteria and dimensional allowances |
| Stainless steel | Corrosion-sensitive mechanisms and custom link fittings | Correct wrought versus cast grade, galling, strength and surface-finish needs |
For instance, wrought AISI 4140-type alloy steel can be considered for heat-treated links, while some aluminum links may be forged from suitable wrought alloys. Do not substitute a wrought alloy designation directly for a cast alloy designation: the available manufacturing route and specifications must match the selected material standard.
Critical Link Arm Geometry and Precision CNC Machining
For many link arms, the decisive dimensional requirements are not the overall outside surfaces but the interfaces that determine movement and load transfer. After forging or casting, precision CNC machining may be used to finish these features.
Pin Bores, Bushing Seats and Joint Interfaces
Bore diameter, roundness, surface finish and position affect press fits, bearing or bushing retention and service clearances. When a link uses a spherical bearing or replaceable pin, the mating part specification should be provided so the correct fit and retaining features can be established.
Hole Center Distance and Alignment
The distance between pivot centers and the relative angle of their axes influence kinematics and assembly. Where multiple bores must work together, the drawing should specify functional datums, center-distance tolerances, orientation and any inspection fixture requirements instead of relying on a general claim of “high precision.”
Transitions, Fillets and Local Stress Concentrations
Fillets at eye-to-arm transitions, changes in section, pockets, threads and weld toes deserve attention because they may concentrate stresses. A manufacturing review can assess draft, machining access, forge flow or castability while preserving the customer’s required clearances and load paths.
Heat Treatment, Surface Protection and Assembly Considerations
Depending on the material and functional specification, link arms may require stress relief, quenching and tempering, precipitation-hardening treatment, or localized hardening of suitable wear surfaces. These are not mandatory steps for every link arm: the chosen treatment must be compatible with the alloy and final design.
Surface finishes may include coating, plating, painting or other treatments as required by the environment and mating components. Particular care is needed around bearing seats, threads and tightly fitted pin bores, where coating build-up can change functional dimensions. See our heat-treatment capabilities and surface treatment information for related services.
If a design contains inserted bushings, pinned joints or separately fabricated elements, assembly sequence, interference fits and any required post-assembly inspection should be included in the production documentation.
Quality Inspection for OEM Link Arms
A link arm may be used in a safety-relevant assembly, but component inspection must follow the specified application and agreed acceptance criteria. SIMIS can discuss inspection planning based on drawings, approved manufacturing procedures and customer requirements; compliance or fatigue performance should only be claimed where supported by applicable tests and records.
| Inspection focus | What may be checked | When to define it |
|---|---|---|
| Material and heat treatment | Material identification, mechanical properties, hardness or heat-treatment records | When grade and property condition are critical |
| Dimensional inspection | Bore diameter, center distance, axis orientation, mounting-face location, threads | For all defined critical-to-function features |
| Surface integrity | Visual checks and suitable NDT where requested or justified by design | For specified load-bearing areas, forgings, castings or welds |
| Coating and assembly | Coating thickness, coverage, bushing fit or joint clearance | When required by corrosion and assembly specifications |
| Functional or fatigue validation | Proof load, bending or cyclic-load testing under an agreed procedure | When prescribed by the OEM or applicable product standard |
For more information about inspection equipment and quality procedures, review SIMIS quality control. The availability, scope and acceptance criteria of project-specific testing should be confirmed during quotation.
Where Custom Link Arms Are Used
The practical manufacturing priorities differ across applications. A forged vehicle suspension arm may emphasize fatigue behavior and pin-to-pin geometry, while a large industrial linkage may prioritize section strength, joint wear and service accessibility.
| Application | Example part | Typical engineering priorities |
|---|---|---|
| Automotive and mobility | Suspension link, control-arm link or articulated steering component | Fatigue loading, joint geometry, corrosion, low mass |
| Construction and mining | Heavy machinery articulation link or rocker arm | Impact loads, bushing durability, access for servicing |
| Industrial machinery | Actuator connecting link or equipment transfer arm | Motion repeatability, alignment, connection fit |
| Robotics and handling | Precision linkage or articulated lever | Weight, stiffness, backlash and dimensional repeatability |
SIMIS also supports related drawing-based enquiries such as hydraulic lift arms and custom brackets and connectors. These related parts may require different process and material choices even when they are used in the same machine.
Design-for-Manufacture Review and Production Planning
A useful DFM discussion begins with the link’s actual constraints: load direction, minimum cross-section, joint size, required motion envelope and assembly method. Manufacturing engineers can then consider billet or blank shape, parting-line placement, machining datum selection, tooling access, heat-treatment distortion and suitable inspection stages.
Confirm the joint design: specify whether bores receive a pin, plain bushing, spherical bearing or direct fastener.
Identify critical versus noncritical dimensions: reserve tighter tolerances for interfaces that affect assembly and movement.
Include load and environmental data: fatigue spectra, shock exposure and corrosion conditions can affect both material choice and process.
Plan for batch size: prototype machining and production forging or casting may have different tooling economics.
Define approval and inspection: agree how critical features will be measured and which test documents are required.
Request a Quote for Custom Link Arm Manufacturing
SIMIS supplies OEM manufacturing services for custom metal link arms rather than off-the-shelf retail replacements. If you have a new mechanism, replacement industrial design or production drawing, we can review the component specifications and discuss a feasible manufacturing route before quotation.
For an efficient RFQ, please provide:
2D drawings and/or 3D CAD files, including part revision and units;
Application and mating-component information, including pin and bushing details;
Material grade or required mechanical properties, with heat treatment where applicable;
Critical tolerances, surface finish, coating and assembly requirements;
Estimated order quantity, annual demand and target delivery schedule;
Specified inspection, traceability, load test or qualification requirements.
Send your files to info@simis-group.com or use the inquiry form below. Quotations and potential manufacturing routes are subject to engineering review of the final drawing and project requirements.
