CNC Machining Ordering Guidelines

To ensure smooth order processing, accurate production, and on-time delivery, please read the following guidelines carefully before placing your CNC machining order.

If you have any questions, please feel free to contact us via Live Chat or email at support@jlcpcb.com.

1. Quotation Rules

Final pricing and lead time for all orders are subject to manual review and confirmation. Automatic quoting is available for some orders for reference only. Final pricing and lead time are subject to manual review results.

Cases Not Supported by Auto Quote:

• High Volume: Order quantity > 20 pcs.
• Complex Files: A single 3D file containing multiple models, bodies, or assemblies.
• Special Features: Parts with unrecognizable features, special materials, or advanced surface treatments.
• Special Processes: Involves specialized machining like EDM (Electrical Discharge Machining).

If the system cannot generate an instant quote or you suspect an inaccuracy, you can still add the item to your cart and submit an inquiry for Free. Our engineering team will review and provide a manual quote within 24 hours.

Note: System-generated quotes and lead times may vary slightly based on production capacity or market fluctuations. The final price and lead time are subject to the manual review result.

2. Lead Time & Shipping

Lead time is determined by and consists of the following factors. When planning your procurement schedule, please take all of these factors into consideration.

Important: If our engineers require any clarification regarding your files during processing, the production clock will be paused until the issue is resolved. Please check your emails promptly to avoid delays.

3. File Formats & Drawing Specs

We strongly recommend uploading both 3D and 2D drawings for the same part.

Supported Formats

• 3D Files (Mandatory): .step, .stp
• 2D Drawings: .pdf, .dwg, .dxf
• Compressed Files: .zip (must only contain the supported formats above)

Critical Blueprint Discrepancy Rules

To avoid production errors, please name your 3D and 2D files identically. In case of conflicts, we follow these priority rules:

1. General Discrepancies: The 3D file takes precedence over 2D drawings.
2. Structural Geometry: Completely based on the 3D model.
3. Special Features: Threaded holes, laser marking, UV printing, tolerances, and surface roughness are strictly based on the 2D drawing.
4. Parameter Conflicts: If your uploaded 2D drawing conflicts with the parameters selected on the ordering webpage, the webpage selections prevail.

Threaded Holes Guidelines

• Webpage Selection: Please check "Threads-YES" when selecting machining parameters.

• 2D Requirements: Upload a 2D drawing detailing exact thread specifications (e.g., Pitch, Depth, type like M8×1.25).
• 3D Modeling Tip: Design the internal thread hole diameter according to the bottom hole size (e.g., for an M8×1.25 tap, model the 3D hole as φ6.8MM.)
• Non-Standard Threads: For custom/special threads, please add a clear note or contact support. View our Threaded Hole Guideline.

4. Machining & Technical Capabilities

• Tolerances: The "tightest tolerance" selected applies only to specific annotated regions on your 2D drawing, not the entire part. If no specific tolerance class is provided, production defaults to ISO 2768 (Class M).
• Maximum Dimensions: Up to 1100 × 600 × 500 mm. Parts exceeding this envelope cannot be processed.
• Internal Corners: Sharp internal corners will naturally be filleted/radiused depending on the cavity depth. Special square-corner requests may incur extra costs. Learn how to optimize costs in our CNC Machining Design Guideline.
• Deep Cavities & Thin Walls: Extreme depths or thin walls may fail tool accessibility checks. Please review geometry limits before ordering.
• Edges & Deburring: All external edges are chamfered/deburred by ~0.2 mm by default. If you require razor-sharp edges, please explicitly mark them on your 2D drawings.
• Wire-Cut/EDM: Features processed via wire-cutting or EDM will have a surface roughness of ≥Ra6.3.

5. Surface Treatment & Aesthetics

• As-Machined (No Bead Blasting): Minor tool marks may be visible. Manual deburring can also cause slight micro-scratches. If you want to preserve the raw machining aesthetics, please leave a note stating "Do Not Polish".
• Anodizing: Anodizing does not include bead blasting by default. If bead blasting is required, please select the anodizing option with blasting.

Contact Marks: Small rack/contact marks are inevitable during the anodizing process. We place these inside hidden or internal holes whenever possible.

Color Variation: Anodized colors may vary slightly between different production batches. Please leave a remark if color uniformity across multiple orders is mandatory.

If you want to know more about appearance details, please check about JLCCNC Appearance Standard Guidelines.

• Deformation Risk: Parts thinner than 10 × 10 × 1 mm are highly prone to warping or bending during surface treatment. Surface treatments are not recommended for ultra-thin parts.

6. Assembly & Multi-Part Projects

• No Assembly Drawings: Our automated system and review team cannot parse combined assembly drawings. Please split your project and submit separate files for each individual part.
• Assembly Relationships: If multiple parts in your order need to fit/assemble together, please leave a clear note in the order remarks so our review team can cross-check fits.

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