Views: 0 Author: Site Editor Publish Time: 2026-06-01 Origin: Site
DINGPRECISION | Tube Fabrication Series — Article C3
DingPrecision Engineering Team | June 2026 | 9 min read
Sourcing lifting column tubes shouldn't feel like gambling. Yet too many manufacturers send an RFQ with nothing more than "70×50mm square tube, black powder coat" — and wonder why the samples bind, the production batch wobbles, and the coating peels after six months.
This guide gives you the 8 specifications every tube RFQ must include, 5 checkpoints for evaluating suppliers, and a downloadable RFQ template.
Outer tube: _____ × _____ mm rectangular
Inner tube: _____ × _____ mm rectangular
Wall thickness: _____ mm
Tolerance: ☐ ±0.1mm (precision) ☐ ±0.3mm (standard)
Why it matters: The tolerance determines whether the inner tube will slide freely after coating. If you don't specify, the supplier will default to standard tolerance — which may not be good enough.
☐ Q235B — Standard for most 2-stage columns
☐ Q345B — Recommended for 3-stage outer tubes or heavy loads (>120kg)
☐ Other: ________
Straightness after fabrication: ≤ _____ mm/m
Post-weld straightening: ☐ Required ☐ Not required
Base plate material: _____ mm thick
Base plate dimensions: _____ × _____ mm
Weld type: ☐ MAG ☐ TIG ☐ Laser
Weld strength requirement: ≥ _____ MPa
Post-weld straightness: ≤ _____ mm/m
☐ Powder coating — RAL _____ — _____ μm — Salt spray ≥ _____ h
☐ E-coating — Black — _____ μm
☐ Zinc plating — _____ μm
☐ Other: ________
Masking required: ☐ Yes ☐ No
Masked zone length: _____ mm from tube end
Masking method: ☐ Silicone plug ☐ High-temp tape ☐ Supplier's standard
If you skip this, expect binding.
Monthly volume: _____ tubes
Initial order: _____ tubes (prototype/sample)
Target lead time: _____ working days
Required certifications:
☐ EN 527 compliance test report
☐ BIFMA X5.5 test report
☐ Salt spray test report (GB/T 10125 or ASTM B117)
☐ Material mill certificate (chemical + mechanical)
☐ Dimensional inspection report (sampling plan)
================================================================
LIFTING COLUMN TUBE RFQ
================================================================
From: [Your Company Name]
Contact: [Name / Email / Phone]
Date: ___________
RFQ Reference: ___________
PRODUCT
----------------------------------------------------------------
Product: Lifting column tube assembly (outer tube + inner tube + welded base plate)
Application: ☐ 2-stage electric standing desk ☐ 3-stage ☐ Other: ____
SPECIFICATIONS
----------------------------------------------------------------
Outer tube: ________ × ________ mm rectangular, wall ________ mm
Inner tube: ________ × ________ mm rectangular, wall ________ mm
Material: ☐ Q235B ☐ Q345B ☐ Other: ____
Tube tolerance: ☐ ±0.1mm (precision) ☐ ±0.3mm (standard)
BASE PLATE
----------------------------------------------------------------
Dimensions: ________ × ________ mm, thickness ________ mm
Material: ☐ Same as tube ☐ Other: ____
Weld: ☐ Full perimeter MAG ☐ Spot weld (________ points) ☐ Other: ____
SURFACE FINISH
----------------------------------------------------------------
☐ Powder coating: RAL ________, ________ μm DFT
Salt spray requirement: ≥ ________ hours (GB/T 10125)
End masking: ☐ Required (________ mm zone) ☐ Not required
☐ E-coating: ________ μm
☐ Other: ____
QUANTITY & TIMELINE
----------------------------------------------------------------
Sample quantity: ________ pcs
Production monthly: ________ pcs/month
First article lead time: ________ working days
Production lead time: ________ working days
Incoterms: ☐ FOB ☐ CIF ☐ EXW ☐ Other: ____
TESTING & QUALITY
----------------------------------------------------------------
☐ Material certificates required (per batch)
☐ Dimensional inspection report required (sampling: ________)
☐ Salt spray test report required (frequency: ________)
☐ Fit test: 100% inner-outer tube slide test
☐ Weld cross-section: 1 per ________ pcs
Additional requirements: ________
ATTACHMENTS
----------------------------------------------------------------
☐ Tube drawing (DXF / STEP / DWG)
☐ Base plate drawing
☐ Assembly drawing
☐ Surface finish specification
================================================================
When evaluating tube suppliers, look beyond the price quote:
# | Checkpoint | What to Ask | Red Flags |
1 | Tube source | "Where do your precision tubes come from?" | "Various suppliers" — means no consistent quality |
2 | Process ownership | "Which processes are in-house vs. subcontracted?" | Cutting, welding, AND coating all at different vendors |
3 | Masking capability | "How do you prevent coating inside the tube ends?" | "We don't usually mask" or "The customer handles that" |
4 | QC traceability | "Can I trace one tube from raw material to shipping?" | Paper-only records, no digital tracking |
5 | Volume scalability | "What's your maximum monthly capacity for this product?" | Capacity equals or barely exceeds your forecast — no buffer for growth |
Pitfall | Consequence | Prevention |
Same tube spec, different mill → different actual dimensions | Inner-outer fit inconsistent between batches | Single-source precision tubes; verify mill certificates match |
Welding shop changes wire brand without notice | Different weld chemistry → different distortion behavior | Lock welding consumable spec in supplier agreement |
Coating shop interprets "powder coat black" as any black powder | Different gloss level, different film thickness, different salt spray | Specify exact RAL code + powder brand + DFT range |
Tubes sit in outdoor storage between processes | Surface rust → poor coating adhesion | Require indoor storage; inspect tubes before coating |
No one owns overall quality → finger-pointing when issues arise | Rework costs absorbed by customer | Contract with single responsible supplier over multiple cheaper vendors |
We produce 400,000 lifting column tubes per month for leading gaming desk brands. Here's what they value most:
1. One supplier, one phone call. From tube to finished column, everything under our roof.
2. 40,000 tubes/month proven capacity. We're not scaling up — we're already there.
3. Proprietary masking process. Our silicone plug method is the result of two years of continuous improvement.
4. 1,000-hour salt spray. Double the EN 527 requirement.
5. No minimum order for prototypes. 50 tubes or 50,000 — same process, same quality.
Request a Custom IP-Rated Enclosure Quote
�� Phone: +86-139-2889-0054
�� Email: niewenhui@dingprecision.com
�� Website: www.dingprecision.com
�� Request a Quote
© 2026 DINGPRECISION | Foshan Dingyi Industrial Technology Co., Ltd.
