How to Develop a Custom Magnetic Car Mount from a Drawing

Published 2026-10-30 · 6 min read

The drawing fixes what the buyer wants; the factory’s job is to confirm which dimensions are functional, which are cosmetic, and which are still unknown before tooling or sampling begins. At our factory, samples run in 7–10 working days and mass production in 7–12 days after approval, with packing and final inspection taking 3–5 days, FOB Shenzhen.

Start With a Drawing Review, Not a Quote

A drawing for a custom magnetic car phone mount usually arrives as a 2D PDF, a 3D STEP file, or a sketch with handwritten notes. Before any quotation, the drawing should be split into three layers: interface dimensions, structural dimensions, and cosmetic dimensions. Interface dimensions include the mounting point, vent clip or adhesive base, and the magnetic head position. Structural dimensions cover wall thickness, rib placement, screw bosses, and the joint between the arm and the base. Cosmetic dimensions cover radii, parting lines, texture, and logo placement.

Any dimension not shown on the drawing must be listed as a pending item. Do not let a supplier fill gaps with assumed numbers. A practical review table looks like this:

For magnetic performance, only two models in our current range use N52 magnets rated at 4100 GS: OX-3 and CX-5. This data must not be applied to other magnetic models. If your drawing calls for a specific holding force, treat it as a test requirement to be verified on the sample, not as a catalogue claim.

Match the Mounting Structure to the Real Installation Point

The mounting structure is where most custom projects fail. A drawing may show a vent clip, but the buyer’s target vehicle may have horizontal, vertical, or angled vanes. The clip geometry, spring force, and contact pads must be reviewed against the actual installation point. Ask the supplier to confirm:

• The clip opening range and whether it is fixed or sprung.
• The contact material and whether it can mark or scratch the surface.
• The adhesive base type, if used, and the surface it is intended for.
• The joint between the mount body and the base: fixed, ball joint, or SK7 shaft.
• The travel range and stop positions, if adjustable.

Our SK7 shaft is tested to 6,000+ cycles. That figure applies to that shaft specification, not to every joint in the range. For a custom drawing, ask for the test method behind any cycle claim: load, angle, speed, and pass criteria. A cycle number without a method is not a purchasing specification.

Also confirm how the mount is assembled. Screws, snap fits, and adhesive joints behave differently in heat and vibration. A drawing that shows a snap fit should include the undercut and the expected assembly force. If the drawing does not show these, the DFM review should flag them before tooling.

Check Phone Case Compatibility Before Cosmetic Approval

Magnetic mounts are sensitive to phone case thickness and material. A drawing that specifies a magnet position and a surface height must be checked against the phone with the case on. The buyer should define the case range: bare phone, thin case, wallet case, or rugged case. Then the supplier can check whether the magnetic head sits close enough to the phone surface and whether the mount arm clears the case edge.

A practical compatibility checklist:

• Measure the phone with the thickest case in the target range.
• Confirm the magnetic head does not contact the case edge or buttons.
• Check that the mount does not obstruct the camera area or charging port.
• Verify the viewing angle with the phone in portrait and landscape.
• Test removal and reattachment several times to check magnet alignment.
• Confirm the mount holds the phone during a simulated vibration check.

Do not name specific phone models in the drawing review. Use generic references such as "your phone" or "the phone" and define the case range by thickness and material. If the drawing includes a magnet pocket, confirm the pocket depth and retention method. A magnet that is loose in the pocket will rattle; a magnet that is over-compressed may crack.

Run DFM, First Sample, and Approval in Sequence

DFM review should happen before the first sample. The supplier should return a marked-up drawing with comments on draft angles, wall thickness, rib placement, gate location, and any features that cannot be molded as drawn. This is also the point to confirm material choice and surface finish. Our factory has 3 production lines, 27 machines, and monthly capacity of 300,000+ pcs, with 4 QC staff across 2 lines. That capacity is relevant only after the drawing is frozen.

The first sample should be checked against a signed checklist, not against memory. A workable approval sequence:

1. Freeze the drawing and record the revision number.
2. Complete DFM review and confirm any drawing changes in writing.
3. Produce the first sample in 7–10 working days.
4. Inspect the sample against the drawing, the checklist, and the agreed test methods.
5. Record deviations and decide whether to revise the drawing or the tool.
6. Sign the golden sample and keep it as the reference for mass production.
7. Confirm packing and final inspection requirements, which take 3–5 days.
8. Release mass production, typically 7–12 days after approval.

For custom projects, MOQ is 50 pcs per model. This is low enough to validate a new drawing without committing to a large order, but it also means the first sample must be reviewed carefully because the tooling and process are still being proven.

On certification: we do not hold CE, RoHS, REACH, or SGS certificates. If your market requires third-party testing, we can arrange it with the test house you nominate, and the cost is quoted separately. Do not accept a supplier’s statement that a certificate "comes with the product" unless the certificate names the exact model and the test scope.

Our documentation includes 8 granted patents from CNIPA: 5 design patents and 3 utility models. We also hold registered trademark no. 80143576 in Class 9 and copyright registration 国作登字-2024-F-00271084. These are useful for checking that the supplier owns the design and brand assets it presents, but they are not a substitute for a drawing review or a sample test.

FAQ

Q: Can you develop from a 2D drawing only, without a 3D file?

A: Yes, but the review will take longer. A 2D drawing often leaves wall thickness, draft, and joint details undefined. We will mark those as pending items and ask for a reference sample or a measured sketch before quoting tooling. If the project is simple, a 2D drawing plus a physical reference may be enough to start the DFM review.

Q: What if my drawing includes dimensions I have not confirmed yet?

A: Keep them as pending items and do not let them be filled with assumed values. The DFM review should list every open dimension and its effect on function, tooling, or cosmetics. Sampling can start only after the critical dimensions are confirmed in writing. This avoids a sample that looks correct but cannot be produced consistently.

Q: How do I verify magnetic strength without a certificate?

A: Treat magnetic strength as a sample test, not a document. Define the test method with the supplier: what the magnet is attracted to, how the load is applied, and what counts as a pass. For reference, only OX-3 and CX-5 use N52 magnets rated at 4100 GS; do not assume that figure applies to a custom model. Ask for the test record with the first sample.

Ready to review your drawing? Send the 2D or 3D file, the target installation point, and the phone case range to WhatsApp +86 198 2632 0305. Our team replies within one working day, Monday to Saturday 9:00–18:00 GMT+8. Product pages: https://feigangxia.com/en/products