A dry-ice cell gets described as ESD-safe with one qualifier attached: with proper grounding. That qualifier is doing the work, not the adjective. Whether a blasted assembly picks up charge depends on the settings the cell runs at and on which surface of the board you put the probe against, so the question for a supplier is not whether the machine is ESD-safe. It is what you will be allowed to measure, where, and at which settings.
The three CHUANGQI dry-ice models publish those settings in full: air flow 0.5–4.0 m³/min, pressure 0.1–0.8 MPa adjustable, pellet feed 0.1–0.6 kg/min, a 1/2 in low-temperature delivery hose, and an IP55 cabinet. None of them publishes an ESD figure. That absence is the honest starting point — the acceptance run is yours to write and yours to perform on your boards, and the machine’s contribution is to hold a setting steady while you do it.
Key takeaways
- An ESD claim without its settings is a sentence, not a specification.
- Grounding drains conductors; it does not drain a solder mask.
- The CQ-C900 publishes 0.5–4.0 m³/min, a range that changes charge generation.
- Record air flow, pressure and feed rate with every acceptance run.
- Conductor and insulator surfaces need separate measurements, not one reading.
The Qualifier Is the Claim: ESD-Safe Applies to a Setup, Not a Machine
Method. This piece is a protocol design, not a test report. It is built from the published settings of the CQ-C900 PCBA dry-ice cleaning machine, the CQ-C7310 dry-ice blasting machine and the CQ-C7320 inline dry-ice cleaning machine, read on 20 October 2026, plus the charge-generation mechanisms those settings expose. We publish no ESD measurement for these machines because we have not run one on your boards, and a supplier figure measured on a supplier coupon would tell you very little.
Read a supplier sentence closely and the structure repeats: the process is safe, given grounding. Grounding is an installation property. Air flow is a setting. The board is yours. Three of the four inputs in that sentence belong to somebody other than the machine builder, which is why the adjective cannot survive contact with a specification review.
What the datasheet does give you is the list of variables that move charge in the first place. Air moving through a hose and across a board separates charge; solid CO&sub2; pellets travelling at speed do the same thing with more mass behind them. The published ranges tell you how much room the cell has to move those variables, and therefore how much of your acceptance result is a function of the recipe rather than the hardware.
| Published setting | Range on the three models | What it moves | Record at acceptance |
|---|---|---|---|
| Air flow rate | 0.5–4.0 m³/min | Friction in the hose and at the nozzle | Set value, not the range |
| Pressure | 0.1–0.8 MPa, adjustable | Jet velocity at the board plane | Set value at the regulator |
| Pellet feed rate | 0.1–0.6 kg/min | Mass of solid CO&sub2; through the hose per minute | Feed setting and block size |
| Delivery hose | 1/2 in, low-temperature rated | One half of the triboelectric pair | Hose length and material |
| Cabinet protection | IP55 | Ingress only; says nothing about static | Do not cite it as ESD evidence |
Source: CHUANGQI published dry-ice machine specifications (CQ-C900 / CQ-C7310 / CQ-C7320), read 2026-10-20. Ranges are published limits; no ESD figure is published for these models.
Two Charge Paths Need Two Different Measurements
Conductor path. A bare pad, an exposed edge, a screw head or the fixture body will accept a ground connection. Charge that lands there can be drained, and the measurement that matters is continuity from the point an operator touches to the reference your ESD program already uses. This is the check most suppliers can support, because it is a hardware property.
Insulator path. Solder mask, conformal coating and connector housings have no path to drain. Charge that lands on a coated surface stays where it landed until the surrounding air removes it. Measuring continuity here is meaningless, and grounding the frame harder will not change the reading. The only tools that act on this path are air ionization and time.
The error that survives audits is a single number labelled board charge. A reading taken on a bare test pad describes the pad. It says nothing about the mask ten millimetres away, and the mask is usually the larger surface. Two probes, two records, two criteria.
Five Checks That Belong in the Acceptance Document
Write these into the purchase order as an annex rather than a promise. Each check names what is measured, where the probe goes, and what the record must contain — the third column is the one that makes a result reproducible a year later.
| Check | What you measure | Where | What the record states |
|---|---|---|---|
| 1 Ground continuity | Continuity to your ESD reference | Frame and operator touch points | Which reference point was used |
| 2 Conductor charge | Surface potential after one pass | Bare pad or board edge | Probe gap and board support |
| 3 Insulator charge | Surface potential after one pass | Mask or coating, a fixed offset (e.g., 10 mm) from check 2 | That it was read separately |
| 4 Ionizer decay | Time to reach your program limit | Nozzle exit and board plane | Distance, ionizer setting, balance |
| 5 Recipe record | The settings the run used | The run itself | Air flow, pressure, feed rate, hose length |
Pass criteria come from your own ESD control program and your device sensitivity class. CHUANGQI does not set them and makes no compliance claim on your behalf.
Check 5 is the one that gets dropped and the only one that makes the other four reusable. A decay time measured at one air flow tells you nothing about the same cell at four times that flow; the published band runs from 0.5 to 4.0 m³/min, so the same hardware can be asked to work in configurations that differ by a factor of eight on the variable most likely to generate charge. Without the recipe, a passing report is a story about one afternoon.
Where This Protocol Does Not Apply
It is not suitable for hand-held blasting where an operator sweeps the jet across a board. The geometry changes continuously, the nozzle-to-board distance is not a setting, and no record can reproduce the run. If that is your process, the acceptance question changes from charge control to operator qualification, and this annex will not carry it.
It is not suitable as a compliance statement. We publish no ESD rating for these cells, we do not certify a line, and a supplier document that certifies your process without seeing your boards should be read as marketing rather than evidence. The pass criteria belong to your program.
It is also not suitable for judging a competitor’s cell from its brochure, ours included. The settings that decide the result are the ones in the recipe record, and no brochure carries them.
FAQ
Is dry ice cleaning safe for electronics?
Dry ice removes contamination without water or solvent, and the published process runs at 0.1–0.8 MPa with 0.5–4.0 m³/min of air. Whether it is safe for a specific assembly is a question about static control, jet energy and component robustness, and it is answered by an acceptance run on your boards rather than by a category claim.
Does grounding the machine remove static from the board?
It drains conductors that are connected to the ground path. It does not drain charge that sits on solder mask or conformal coating, because there is no conductive path to drain. Those surfaces need ionization and time, which is why checks 3 and 4 exist separately from check 1.
Do we need an ionizer with a dry ice cell?
If your boards carry coated surfaces in the blast path, a grounded frame alone cannot address them. Whether an ionizer is required, and at what distance it must be mounted, follows from your program’s limits and from a decay measurement at board level. We do not publish an ionizer specification for the cells.
Can the machine supplier certify ESD compliance for our line?
A machine builder can document settings, grounding points and installation conditions. Certification of your line belongs to your ESD program and your auditors. We will supply the connection data and hold a setting through the acceptance run, and we will not sign a compliance statement we cannot measure.
If you are writing that annex, send us your board type and the ESD program you already run and we will return the connection data and a draft acceptance sheet with a quote within 24 hours. The general acceptance structure for a cleaning machine sits in our factory acceptance test guide, the waterless process itself in dry ice blasting in electronics, and the cell specification on the CQ-C900 PCBA dry ice cleaning machine page.