Once you decide to use CCGA spring columns, the next big question is:
“What exactly should we put in the drawing and RFQ so suppliers can quote properly and we can pass reliability qualification?”
If your specification is too vague, you will spend weeks going back and forth.
If it is over-constrained, you may lock yourself into a single source.
This guide is a practical checklist to help you specify spring columns for real projects.
1. Start from the mission profile
Before talking about alloys and diameters, start from how and where the product will be used:
- Operating temperature range
- Storage temperature
- Thermal-cycling or power-cycling profile
- Vibration and shock environment (vehicle, aerospace, industrial, etc.)
- Target service life in the field
Even a simple table like this is enough to start a productive discussion:
| Parameter | Example value |
|---|---|
| Operating temperature | −40 to +105 °C |
| Storage temperature | −55 to +125 °C |
| Thermal-cycling profile | −40 ↔ +125 °C, 1000 cycles |
| Vibration environment | Automotive-grade, random vibration |
| Target lifetime | 10+ years |
Once this is clear, your supplier can recommend an appropriate column structure and alloy system.
2. Choose column geometry: length and diameter
Column length and diameter strongly influence both mechanical compliance and current-carrying capability.
Basic rules of thumb:
- Longer columns
- More compliance and better fatigue life
- Higher component profile
- Stricter coplanarity requirements
- Larger diameter
- Higher current capacity and mechanical strength
- Lower flexibility
- Larger pad size on both package and PCB
When we review a design, we usually balance:
- Package size and pitch
- PCB thickness and stiffness
- Maximum allowed component height
- Stencil and assembly constraints
By sharing your package information, you allow the supplier to propose a length/diameter combination that has already worked in similar applications.
3. Select the alloy family
For spring columns you typically see:
- High-lead or specialty alloys for very wide temperature ranges and extreme environments
- Lead-free alloys when regulations or internal policies require them
The choice depends on:
- Peak operating and reflow temperatures
- Required number of thermal cycles
- Applicable environmental regulations
- Internal reliability targets
In many mission-critical designs, reliability performance is still prioritized over pure material cost. A good supplier should walk through the trade-offs with your materials and quality teams.
4. Define coplanarity and inspection criteria
Columns are only as reliable as their geometry and attachment quality.
In your specification, clearly define:
- Maximum coplanarity tolerance across the full array
- Visual inspection criteria (bent columns, deformation, contamination)
- X-ray inspection targets (voiding, wetting, fillet shape)
- Any special requirements for corner joints or critical nets
Clear criteria will make incoming inspection at your EMS much faster and reduce disputes later.
5. Coordinate with your assembly process
Spring columns behave differently from BGA balls during reflow and cleaning, so bring your process engineers into the discussion early:
- Stencil design and solder paste volume
Ensure sufficient solder to build a robust joint around the column foot, without causing bridging. - Reflow profile
Check that your oven capability matches the selected alloy and component mass. - Cleaning
Confirm that flux residues can be effectively removed under and around the columns, or validate your no-clean process.
Often, small adjustments to stencil design or profile save a lot of time and scrap during NPI.
6. What to include in your RFQ
To get meaningful, comparable quotations, your RFQ for spring columns should at least include:
- Package drawing with pad layout
- Pitch, pin count, and body size
- Target column length and diameter, or acceptable ranges
- Required or preferred alloy family
- Mission profile summary (temperature, cycles, environment)
- Reliability and test requirements
- Expected annual demand and project lifetime
You can treat the following as a simple internal checklist before you send the RFQ:
| RFQ item | Included? |
|---|---|
| Package drawing (with pad layout) | ☐ |
| Pitch, pin count, body size | ☐ |
| Column length & diameter range | ☐ |
| Alloy requirement / preference | ☐ |
| Mission profile summary | ☐ |
| Reliability / test requirements | ☐ |
| Annual demand & project duration | ☐ |
The more complete this information is, the faster your supplier can respond with a realistic technical and commercial proposal.
7. A typical collaboration flow with a technical supplier
For new spring column projects, a straightforward cooperation model works best:
- Technical exchange
You share your drawings and mission profile; the supplier asks a few focused questions. - Preliminary recommendation
They suggest a spring column configuration and, if helpful, a test plan. - Sample and prototype stage
You receive samples or built-up parts for lab builds and qualification tests. - Feedback and optimization
Column parameters or process windows are fine-tuned based on your test results. - Mass production and ongoing support
Engineering support continues during full production, not only in the NPI phase.
Need help specifying spring columns for your design?
If your team is working on a new CCGA package or upgrading an existing one and you are not completely sure how to specify spring columns, we can support you.
Send us:
- Your package drawing
- Key PCB parameters or stack-up
- Target operating conditions and lifetime
and our engineers will help you turn this into a clear, supplier-ready specification — together with matching spring column solutions from our production.
Interested in a design review?
Contact us through the enquiry form on this website or email our technical sales team to discuss your project and request a consultation.