Internal Passages: Burr Allowance Max 0.1 mm

Component Specifications

Definition

Internal passages are intricate, precisely engineered channels integrated into the structure of a manifold body, designed to route hydraulic or pneumatic fluid with minimal pressure drop and turbulence. They form the core flow network connecting inlet/outlet ports, valve cavities, and actuator interfaces, enabling complex control logic within a compact assembly. Their design is critical for system efficiency, response time, and leak prevention.

Working Principle

Internal passages operate on fluid dynamics principles, guiding pressurized fluid (hydraulic oil or compressed air) from source ports through the manifold to control valves and ultimately to actuators (cylinders, motors). Their cross-sectional geometry, surface finish, and routing minimize flow resistance (pressure loss) and fluid hammer, ensuring precise and rapid system response. They are sealed by the manifold body itself, eliminating external tubing for internal connections.

Materials

Typically machined from: Carbon steel (e.g., AISI 1018, 1045) for general hydraulics; Aluminum alloys (e.g., 6061-T6) for lightweight pneumatic systems; Stainless steel (e.g., 304, 316) for corrosive or high-purity applications; Ductile iron for high-pressure durability. Internal surfaces often have a machined finish of Ra 0.8-3.2 μm.

Technical Parameters

Parameter	Typical range	Notes & selection driver
Tolerance	±0.1 mm on diameter, ±0.5° on intersection angles
Burr Allowance	Max 0.1 mm
Surface Finish	Ra 0.8-3.2 μm
Pressure Rating	Up to 350 bar (hydraulic), 10 bar (pneumatic)
Passage Diameter	3-25 mm (common range)
Intersection Geometry	Drilled, cross-drilled, or milled channels

Ranges are indicative industry figures for RFQ preparation, not a supplier commitment. Confirm every value and standard with the legal manufacturer before ordering.

Standards

ISO 4401, ISO 5599/1, DIN 24340, NFPA T2.6.1

Parent Products

This component is used in the following industrial products

Manifold Body

The main structural housing of a vacuum manifold that provides the framework for connecting and distributing vacuum lines.

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Manifold Block

A solid block with multiple internal passages that distributes fluid or air to multiple control valves in a centralized system.

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Manifold Block/Body

The main structural component of an inert gas supply manifold that houses internal passages and connection ports.

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Engineering Analysis

Risks & Mitigation

Fluid leakage at passage intersections
Excessive pressure drop due to poor design
Contamination trapping in dead-end passages
Erosion or corrosion of channel surfaces
Cracking from high-cycle fatigue

FMEA Triads

Trigger: Improper machining tolerances or misaligned drill intersections
Failure: Internal leakage between adjacent passages, reducing system efficiency
Mitigation: Implement precise CNC programming, use coordinate measuring machines (CMM) for verification, and apply pressure testing during quality control.

Trigger: Inadequate deburring or rough surface finish
Failure: Increased turbulence, pressure drop, and potential contamination shedding
Mitigation: Specify Ra surface finish requirements, perform abrasive flow machining (AFM) or tumbling, and include visual/ tactile inspections.

Trigger: Material defects or improper heat treatment
Failure: Passage wall cracking under high pressure or cyclic loading
Mitigation: Use certified materials, apply non-destructive testing (e.g., dye penetrant), and follow standardized heat treatment protocols (e.g., ASTM A29).

Industrial Ecosystem

Compatible With

Typical Suppliers & Equivalents

Compliance & Inspection

Tolerance

Dimensional per ISO 2768-m, pressure integrity per ISO 4413 (hydraulics) or ISO 8573-1 (pneumatics)

Test Method

Pressure decay test, flow capacity test, burst pressure test, and cleanliness testing per ISO 4406

Procurement Evaluation Criteria

A practical evidence checklist for RFQ preparation and supplier evaluation.

Technical documentation

Request current drawings, revision history, and a signed specification sheet.

Manufacturing capability

Verify equipment lists, process limits, capacity, and representative production evidence.

Inspection readiness

Confirm test methods, calibrated equipment, sampling plans, and traceable reports.

Supplier transparency

Check the legal entity, factory address, ownership, certifications, and direct contacts.

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Manufacturers of Internal Passages

Manufacturer profiles associated with Internal Passages.

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Compiled and source-reviewed by the CNFX editorial team. Each manufacturer above links to the page on that company's own website where the product is listed, with the date we checked it. How we source and review

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Seal Groove

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Frequently Asked Questions

What is the primary function of internal passages in a manifold?

To direct hydraulic or pneumatic fluid between ports, valves, and actuators within a single compact block, eliminating external piping for internal connections and reducing potential leak points.

How are internal passages typically manufactured?

They are precision-machined using CNC drilling, milling, or gun-drilling processes, followed by deburring and surface finishing to ensure smooth flow and prevent contamination.

What factors influence the design of internal passages?

Key factors include fluid type (hydraulic/pneumatic), operating pressure, flow rate requirements, pressure drop limits, space constraints, and compatibility with standard porting patterns (e.g., CETOP, NFPA).

Data Basis

Editorial classification, named public sources where available, and source-reviewed manufacturer records. See the editorial policy.

Preliminary Technical Classification

This page supports structured research, RFQ preparation, and supplier evaluation. It does not replace buyer-led supplier qualification, standards review, or technical approval.

Internal Passages

Component Specifications

Parent Products

Manifold Body

Manifold Block

Manifold Block/Body

Engineering Analysis

Industrial Ecosystem

Compatible With

Typical Suppliers & Equivalents

Compliance & Inspection

Procurement Evaluation Criteria

Manufacturers of Internal Passages

Related Components

Frequently Asked Questions

What is the primary function of internal passages in a manifold?

How are internal passages typically manufactured?

What factors influence the design of internal passages?

Data Basis

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