Copper busbars and terminal plates
Hole positions, bolt clearances and contact areas need to match the assembly. Mark any faces that must stay free of coatings or handling marks.
Copper parts for electrical and thermal assemblies
4 part examples
Heat spreaders and base plates
Identify the thermal interface, mounting pattern and flatness requirement. Specify the finished surface rather than asking for a uniformly polished part.
Pocketed blocks and housings
Send the model with pocket depths, threaded ports and mounting features. For a fluid-carrying design, agree sealing and leak-test requirements separately.
Turned contacts and stepped pins
Call out the contact diameter, shoulder locations and mating part. Include the final plated dimensions when the component fits into a connector or fixture.
Which copper grade does your part need?
C11000 — electrolytic tough-pitch copper
A high-conductivity copper used for electrical components. Quote the specified stock form and temper; the grade name alone does not define the finished part. [1]
- Where to start the discussion
- Busbars, terminal plates and general conductive components.
- Before approving the material
- Confirm oxygen-related requirements before any proposed alternative.
C10200 — oxygen-free copper
An oxygen-free, high-conductivity grade. Use the exact designation and product standard on the drawing rather than treating “OFHC” as a complete material specification. [2]
- Where to start the discussion
- Conductive components for drawings that call for oxygen-free copper.
- Before approving the material
- Identify joining conditions and any additional material evidence.
C10100 — oxygen-free electronic copper
An oxygen-free electronic grade with tighter purity requirements than general oxygen-free copper. State the full material specification and the records needed to confirm it. [3]
- Where to start the discussion
- Electronic or vacuum-related designs with an explicit C10100 requirement.
- Before approving the material
- Material grade alone is not proof of vacuum or system qualification.
C14500 — tellurium copper
Tellurium is added to improve machinability while retaining high electrical conductivity. It is an alloyed copper, not a like-for-like replacement for C10100 or C10200. [4]
- Where to start the discussion
- Turned contacts, machined connectors and other specified screw-machine parts.
- Before approving the material
- Confirm conductivity, joining requirements and substitution approval.
Copper grade, temper and stock form
Specify the copper grade, material standard and edition, temper and stock form. Required material certificates must identify the supplied batch.
| Property | C11000 ETP copper UNS C11000 | Condition |
|---|---|---|
| Density (g/cm³) | ≈8.91 | 20°C |
| Electrical conductivity (% IACS) | 101 | 20°C |
| Thermal conductivity (W/(m·K)) | ≈391 | 20°C |
Physical values are at 20°C; select the temper separately for strength and forming requirements.
Copper milling, turning and drilling
Milled pockets and flat mounting faces
For plates and blocks, mark which faces locate the assembly and which pockets need a controlled finish. We review tool access, wall support and the relationship between features before confirming a machining plan.
Turned diameters, shoulders and threads
For pins, contacts and cylindrical parts, include fit tolerances, shoulder locations and the thread specification. Repeated diameters or coaxial features should share a clearly defined datum system.
Drilled holes and connected passages
Show hole depth, position and entry details. Where drilled passages connect inside a block, agree how the internal intersection will be deburred, cleaned and checked.
Electrical contacts and thermal interfaces
Electrical contact faces
Mark the mating area, fastening arrangement, coating and any contact-resistance acceptance criteria. The material conductivity value does not, by itself, define the resistance or current rating of an assembled joint.
Thermal interfaces
Identify the mounting face, flatness, roughness and interface material used by your design. State where measurements are required, rather than applying a decorative polish to every surface.
Joined or sealed assemblies
Include the planned soldering, brazing or sealing process in the inquiry. Agree which surfaces must remain uncoated and when final inspection is performed.
No assembly requirement selected.
System ratings, joint performance and application qualification need design-specific validation. The machining quote should identify the part characteristics to be checked.
Finishes for copper parts and contact surfaces
As machined
For a part delivered without plating, define tool-mark acceptance, burr removal and how exposed faces should be protected during handling.
Agree cleaning and packaging before shipment.
Tin plating
Specify the tin-plating process, thickness, coverage and any underlayer. Mark masked areas and identify the joining or contact requirements that the coating must meet.
Give the finished dimensions after plating, together with the plating thickness range the drawing allows.
Nickel plating
State whether the drawing calls for an electrolytic or electroless nickel process. Include the specification, thickness and required inspection records.
Do not substitute one nickel process for another without approval.
Silver plating
Provide the coating specification, any underlayer, thickness and coverage. Include storage, handling and any defined contact-performance acceptance criteria.
Specify the plating process, thickness and required appearance. Finishing availability and responsibility are confirmed with the quotation.
Copper tolerances, flatness and inspection requirements
| Feature | Specification | Acceptance condition | Verification |
|---|---|---|---|
| Material conductivity | Grade; condition; conductivity limit and units | Specified test temperature and sampling | Measured conductivity; test-method record |
| Contact diameters and holes | Size limits; datums; mating part | Before/after coating; masked features | Size and fit measurements |
| Flat thermal or mounting faces | Flatness; thickness; datums; measurement area | Defined support; finished inspection stage | Face geometry and thickness checks |
| Surface finish | Roughness parameter/units; locations; permitted marks | Functional, cosmetic and general areas identified | Roughness and separate appearance checks |
| Threads and sealed features | Thread standard/class; sealing method; mating details | Specified dimensional and functional acceptance | Separate thread, pressure and leak checks |
We confirm the tolerance against your actual copper part rather than quoting one figure for all of them. Geometry, stock condition, coating and the measurement method are reviewed before the order is accepted.
Details to check before machining copper
Give thin features enough support
Identify fins, narrow walls and long unsupported sections in the model. Where the design allows it, discuss a different workholding area or machining sequence rather than changing the finished part without approval.
Make burr requirements specific
“Deburr” should not leave the treatment of a sealing edge or contact face open to interpretation. Show edge breaks, areas where rounding is not allowed and internal intersections that need attention.
Keep the model and drawing at the same revision
The model defines geometry; the drawing carries dimensions, datums and acceptance requirements. Supply matching files and identify any conflict before material is ordered.
Inspect contact faces after plating or joining
Plating, cleaning or joining can introduce additional acceptance steps. Identify the final dimensions and surfaces that need to be checked after these operations.
Discuss drawing-review requirements
No review topics selected.
Material records, inspection and protective packing
Match the material record to the order
Request the required certificate with the material designation, condition and batch identification. State whether conductivity (%IACS) or other test results must appear on the certificate, since a standard mill certificate reports composition only.
Agree what appears on the inspection report
List reportable dimensions and features, the measurement method and the agreed sample size. Coating thickness, cleanliness or electrical checks should be listed separately when the project requires them.
Protect the surfaces you will assemble
Mark faces that must be kept free of dents, scratches or fingerprints. Agree separation, wrapping, identification and storage conditions appropriate to the finished component before packing.
What changes the cost of a copper part?
Grade and starting stock
The specified grade, temper, stock size and required evidence shape the material quotation. An approved alternative must be discussed explicitly; it is not automatically substituted to reduce cost.
Geometry and finish
Small features, deep passages, contact faces and multiple setups add work to the process plan. Quote coating thickness, masking and inspection together with the machined component.
Samples and repeat quantities
Separate the first sample quantity from later batches. This makes setup, approval, finishing and delivery requirements visible instead of treating a prototype price as the repeat-order price.
From your drawing to a repeat copper-parts order
Review the drawing
Send matching files, the copper specification, quantities and the required finished condition. Identify open questions before approval.
Confirm scope and samples
Agree material, machining, finishing, inspection and who will perform each operation. Define whether a sample needs approval first.
Make and inspect the parts
Work to the approved revision and agreed checkpoints. Changes in requirements or the production arrangement need confirmation.
Pack and keep the record
Use the agreed marking and packaging. For a repeat order, check the revision, quantity and any changed application requirements.
Questions about copper CNC machining
Which copper grades can I specify for CNC machining?
Start with the grade on your drawing. This page covers C11000, C10200, C10100 and C14500 as discussion options. Stock form, temper, material records and machining feasibility need to be confirmed for the particular order. Other grades can be reviewed from your full specification.
What is the difference between C11000 and oxygen-free copper?
C11000 is electrolytic tough-pitch copper. C10200 is oxygen-free copper and C10100 is oxygen-free electronic copper. These names describe different material specifications, not interchangeable marketing labels. Include the exact grade and relevant product standard when requesting a quote. [1] [2] [3]
When should I ask about C14500 tellurium copper?
C14500 is worth discussing when your design permits a machinability-focused copper alloy. The tellurium addition improves cutting behavior while retaining high conductivity. It should not replace a specified pure or oxygen-free grade without checking the application and obtaining approval. [4]
Does a copper grade guarantee the current rating of my assembly?
No. A machining order should specify the part and any required tests. The assembly design, contact interface and operating conditions need their own validation. We do not assign a current rating from the copper grade or the shape of a sample image.
Should I specify tolerances before or after plating?
Make that explicit on the drawing. When a plated diameter, contact face or thread is functional, provide the coating specification, thickness and final dimensions. Also identify masked surfaces and the inspection stage.
Can the inquiry include conductivity testing or a material certificate?
Yes. Specify the records or tests required, including the method, units, conditions and sampling where applicable. The quotation will confirm which documents and tests are included.
What files do you need for a copper machining quote?
Provide a matching 3D CAD model and dimensioned drawing where available, plus the grade, temper, quantity, finish and inspection requirements. The inquiry form accepts STEP, IGES, PDF, DWG, DXF, SLDPRT or a ZIP package up to 20 MB.
Will a partner factory be involved?
That depends on the project. If additional machining, finishing or inspection is needed, we will discuss the arrangement and responsibilities. You can also ask for a direct introduction rather than having VETCNC coordinate the entire order.
Request a quote for your copper parts
- Matching CAD model and dimensioned drawing
- Copper grade, material standard, stock form and temper
- Contact faces, thermal interfaces, fits and surface requirements
- Plating, masking, cleaning and inspection records
- Sample and batch quantities, approvals and requested arrival date
Agree confidentiality and the transfer method before sharing sensitive or restricted files.
PROJECT SUPPORT
Discuss your copper part
Share your drawing, material and quantity. Tell us what you need and we will reply by email.
Material references and specification notes
- Copper Development Association — C11000 — Electrolytic tough-pitch copper designation and material data.
- Copper Development Association — C10200 — Oxygen-free copper designation and material data.
- ASM International — UNS C10100, Oxygen-Free Electronic Copper — Oxygen-free electronic copper for electrical and electronic applications.
- Wieland Concast — C14500 Tellurium Copper — Tellurium-copper machinability, conductivity and material characteristics.
References for copper grades and material designations. Use the current product specification, material certificate and approved drawing for procurement.
