充电桩外壳换料怎么走?分件选料与耐候复验

应用领域 发布时间: 2026-09-12 4588 阅读

When changing the material of the charging pile's casing, the requirements for the pile body and the gun casing are often opposite. This article explains why the two parts need to select materials separately, which data points should be checked during weather resistance re-testing, how to read the judgment table, as well as the processes that need to be modified when the materials are changed, and what to check in each of the three rounds of mold testing.

The issue of changing the material of the charging pile enclosure caused a charging pile manufacturer to get held up during acceptance inspection last year.

They switched the pile casing from the material they had been using for many years to ours, citing that the delivery cycle of the raw material was getting longer and longer.

The samples were successful, and dozens of units were installed for trial operation. After one summer, the light-colored casings began to yellow, and the gloss also faded.

The client only replied with one sentence: 'The item isn’t cracked, but the color is wrong, and the carrier won’t accept it.'

The second sentence he said on the phone is even more worth remembering: 'We have done UV resistance tests, and the report is qualified.'

I first asked him three counter-questions: Was it just the pile shell that was replaced, or was the gun shell replaced as well? Did the weathering test use xenon lamps or ultraviolet lamps, and what was the accumulated energy delivered? Were the flame retardancy and electrical tracking retested after aging?

He answered: Pile body; xenon lamp, energy according to the magnitude reported in the old report; retesting after aging was not done.

The line below shows the complete process of this batch of shells.

The starting point is that the sample passes both appearance and conventional performance tests, so it’s released for trial operation; the latent phase is the first summer with strong UV and high temperatures combined, causing the surface to begin to lose gloss; the outbreak happens when the second batch of complete machines is inspected and the color difference exceeds the limit, leading the operators to reject them; the settlement is upon review, finding that the root of the color issue lies in the formulation proportions — the toughening and flame-retardant components were increased, while the portion for weather resistance was squeezed.

In the end, when it comes to changing the outer shell, most of the accounting comes down to three words: sunbathing.

1. The working condition of the pile body shell, first drop the numbers for the four samples in six dimensions

The pile body shell is a typical large outdoor item, and not a single one of the six lines can be omitted.

Ultraviolet is listed first because it is one of the few types that 'get worse the more they are exposed and irreversible.'

A common practice in the industry is to convert the cumulative irradiation energy of xenon lamps, compressing several to more than ten years of outdoor exposure into just a few hundred to over a thousand hours.

The temperature should be calculated based on the panel temperature, not the air temperature.

It is common for metal or dark-colored panels at noon in summer to have surface temperatures twenty to thirty degrees higher than the air temperature; the temperature difference between the inside and outside of the component will add another layer of stress on the assembly surface.

This cycle needs to be recorded separately: the day-night temperature difference occurs more than three hundred times a year, and over ten years of service, it amounts to over three thousand times.

For coastal scenarios, salt spray should also be added, with the level determined by the number of hours of neutral salt spray, and the stress on metal parts and coatings becomes more pronounced.

In terms of electrical aspects, this is a tough requirement for the pile body: flame retardancy must be reported according to the minimum wall thickness, electrical tracking must be measured in a humid state, and both need to consider changes after aging.

The remaining two are mechanics and lifespan: falls mainly impact the gun casing, while the pile body is more affected by wind load and compression; the lifespan is calculated at ten to fifteen years, and for exterior parts there is an additional requirement for color difference without repainting.

Among the six items, ultraviolet, electrical tracking, and flame-retardant aging need to be retested first, as they determine the subsequent course of action.

Two or three routes, placed side by side

Changing materials is not about picking a 'universal material'; it's about clarifying the costs of the three options.

RouteWeather resistance and appearanceFlame Retardant and Electrical TrackingSize and WarpageWhere is it suitable to change from?
PA6-GF Weather-Resistant SystemThe ultraviolet system is complete, and color control is relatively easy to handle.Needs to be matched with the flame-retardant systemLarge thin-walled warping needs to be pressedOriginal general-purpose reinforced material, small and medium-sized housings
PA66-GF Weather-Resistant SystemThe temperature tolerance margin is one level higher, and the risk of yellowing is greater.The compatibility range between flame retardancy and tracking resistance is relatively wideModerate warpingOriginal PA6 lacks sufficient strength or the temperature is too high
Component plan: skeleton panelThe exterior panel can be mineral-filled or non-reinforcedFlame retardancy relies on the backboneWarping is most controllableLarge-sized pile with high appearance requirements

None of the three is better; it’s just a matter of which one suits your structure and appearance requirements.

A common misjudgment is treating 'weather-resistant modification' as just applying a layer of protection.

Weather resistance is not just a surface matter; it is a part of the formulation: UV absorbers, light stabilizers, and antioxidants all need to have their place.

The toughening agent and flame retardant are added, occupying this position — this is most noticeably amplified on the outer casing parts.

Another misjudgment is treating the pile and the cartridge case as a single piece when selecting.

The pile body must be rigid, weather-resistant, and warp-resistant; the gun shell must be tough, not break in low temperatures, and also have a good grip feel.

The preferred directions of the two parts are opposite, and using the same batch of material to handle them usually results in neither side being good.

3. Material Change Criteria Table: This table determines which items you need to re-inspect

Turn the previous constraints into verifiable indicators.

The thresholds in the table are directional suggestions, not acceptance standards; the actual values need to be determined by your equipment, your outdoor conditions, and your own measurements.

IndicatorDirectional ThresholdVerification Method / StandardCommon failures after material changeCommon solutionCorresponding auxiliary agent system
Xenon lamp aging color differenceAfter accumulating energy, ΔE is within the allowed rangeISO 4892-2 / GB/T 16422.2Yellowed, dulledComplete the weathering system and retestUltraviolet Absorber Hindered Amine Light Stabilizer
Mechanical retention after agingRetention rate according to the whole machine specificationsTensile / Impact after aging (ISO 527, ISO 179)Becomes brittle after surface powderingStabilization system Control material temperatureAntioxidant (inhibits degradation)
Low temperature shockDoes not crack at low temperaturesGB/T 1043 / ISO 179, low-temperature chamberWinter fall and shatterToughening System Structural FilletToughening agent
CTI (wet state)Measure in wet condition according to the machine gearIEC 60112, conditioned stateDrops one gear after agingLow moisture-absorbing substrate Anti-fouling structure—(Material grade)
Flame retardant (after aging)Report V-0 according to minimum wall thicknessUL94 / IEC 60695-11-10Flame retardancy degradation after agingChange the flame retardant system and retestHalogen-free flame retardant
Assembly surface warpingFlatness within the drawingCMM / Assembly GaugeUneven assembly seams, poor sealingParting or mold repair—(Structural and Process Attributes)
Surface conditionFloating fibers and luster in the color swatchVisual inspection Glossiness Color swatch comparisonFloating fibers, flow marksForm removal temperature, gate adjustmentLubricant (improves flow)

How to read this table: first look at the first two rows.

Color difference determines whether it can pass inspection, and retention rate determines whether it can last for the intended service life; both belong to the same aging curve.

If these two lines can't pass, no matter how good the subsequent intensity data is, it is meaningless.

The third column is for procurement and quality: the aging report must specify the cumulative energy and the thickness of the test piece; reports of short duration cannot be used as long-term conclusions.

4. Four types of failures after material replacement, and their real causes

Failure 1: After one summer, the light-colored items turn yellow and lose their shine.

There are usually two root causes: insufficient proportion of weathering additives, or part of the additives being consumed prematurely due to processing temperature.

The pattern we observed is: for the same formula, if the toughness and flame retardancy are each increased slightly, the weather resistance part tends to become thinner.

This doesn’t mean the material is bad; it’s about making trade-offs in the formula proportions, and weather resistance is the easiest to sacrifice in these trade-offs because it doesn’t show immediately.

Failure 2: Surface fiber float and uneven gloss.

The root cause lies in the mold temperature and the gate, not in the substrate.

If the mold temperature is insufficient, the glass fibers at the front end of the material flow are exposed on the surface, and under light they form whitish streaks; if the gate position is not ideal, flow marks will remain on the appearance surface.

This type is resolved through process windows and cannot be solved by changing the material number.

Failure 3: Warping of the assembly surface of large thin-walled parts.

The root cause is the shrinkage anisotropy caused by the orientation of the glass fibers.

A half-meter-long machine casing, if the assembly surface is off by just a few tenths of a millimeter, the door gap will be uneven, and the sealing strip will also be strained.

On paper, it seems like a size issue, but at its root, it's a problem with the flow channel and orientation.

Failure Four: After aging, the electric tracking drops by one level.

The root cause is three things piling up together: moisture absorption, surface deposition, and carbonization under voltage.

The rougher the surface, the more easily it accumulates dirt and moisture; once the surface is carbonized, the leakage current flows along the carbonized layer and cannot return even if it rises again.

For this type, we need to look at the wet-state data after aging; the qualified values on the day of manufacture do not indicate the problem.

5. Processing and Verification: After disassembly, the processes should also be separated.

Sorting materials by component is not just about taking the pieces apart; the processes must be divided accordingly.

For this set of exterior panels, the focus is on surface condition and color difference: the mold temperature should be stable, the material temperature should not reach the upper limit of the additives, and the demolding and handling techniques must be clean.

For this set of the framework, the focus is on flame retardancy and rigidity: pressure holding and cooling need to be controlled, and allowances for warping should be incorporated into the structure, not entirely blamed on the material.

The drying process cannot be skipped for either of the two types of materials.

The outer shell parts commonly use glass fiber systems; after unpacking and leaving them exposed for a few hours, their moisture content will rise again. Before processing, confirm the moisture level with a moisture meter or dew point measurement, not by hand feel.

Assembly and post-processing are the third step.

If the panels and the skeleton are molded separately and then assembled, the cleanliness of the bonding surfaces or snap-fit positions must be controlled; the most common complaint with the parting scheme is that the cleanliness of the assembly surfaces was not properly managed.

It is recommended to arrange the verification sequence like this, do not change it:

1. Material level: color difference and retention rate after cumulative energy of xenon lamp, wet electrical tracking, thin-wall flame retardancy

2. Process window: Compare different mold temperatures and gate arrangements to check for floating fibers and warpage.

3. Component Level: Assembly surface flatness, drop and low-temperature impact (handled separately for the cartridge case)

4. Retesting after aging: flame retardancy, tracking resistance, sealing, and assembly dimensions

5. Whole machine: Install on the pile to run outdoors under sun exposure and rain, and inspect the appearance again according to the season

Why can't the order be changed? Because both appearance and electrical performance depend on the surface condition and moisture absorption state; if the surface isn't fixed, the aging data will only be valid for that batch.

6. Boundary: For these types of shells, stop handling the material first when changing it.

This section may be more valuable than the previous few sections because it helps you cut losses before starting work.

First, the pile body is of super-large size, requires one-time forming, and its appearance must not have floating fibers.

These three requirements all pressing on one type of material can usually only be solved by splitting the parts or changing the molding method; forcibly changing the material code is just filling in time.

Secondly, the target market includes projects with both strong ultraviolet exposure and coastal conditions.

The weathering grade and salt spray requirements will both be raised, the verification cycle will be extended accordingly, and this should be taken into account before reporting the delivery date.

Thirdly, the cartridge case requires extremely low-temperature resistance without shattering, and also requires high rigidity.

These two directions constrain each other, requiring structure to solve rigidity, and materials to maintain toughness.

Fourth, thin-walled large parts that cannot have rounded corners or be split into pieces structurally.

The stress concentration point cannot be eliminated; changing the material only postpones the problem.

Fifth, parts whose failure points have not yet been located.

Yellowed, warped, or broken, first distinguish whether it is weather resistance, orientation, or impact; the solutions for these three issues are completely different.

Putting these five points at the front is not to discourage, but to save time.

7. Material Change Risk List (things that need to be changed when switching from the original plan to this one)

link; segment; partWhat do you want to move?Points that are easy to overlook
MoldThe shrinkage rate has changed, the assembly surface and the snap-fit positions need to be re-measured.Only replace the material without repairing the mold, the door gaps are uneven
DryReplace the dehumidifying dryer and set the window according to the measured moisture content.The exposed surface regains moisture after a few hours.
Humidity controlKey fitting dimensions are drawn in the conditioned stateKey mating positions are released according to the dry state
Material Temperature / Mold TemperatureSurface condition and weld line relocation, mold temperature must be stableMaterial temperature reaches the upper limit of the additive
Pressure Holding / DemoldingThe shrinkage compensation for large thin-walled parts needs to be rearrangedThe pickup method left scratches
Color differenceLight-colored parts are harder to match than dark-colored parts, so prepare the color board in advance.There is a difference in the base color between batches
Component assemblyCleanliness of the bonding surface between the panel and the frameAssembly surface contaminated with oil
Verification orderMaterial → Process → Component Level → Retest After Aging → Whole MachineIf the previous item fails, just move on.

8. Sample Mold Trial Schedule (How many rounds of machine use, what to test in each round, how long to retain)

We usually do three rounds of mold trial for the pile shell material change row, with no skipping between rounds.

First round · Small sample comparison: Use your original mold to make three to five molds, check flowability, appearance, weld line and floating fiber position, and confirm moisture content after drying.

This round doesn't focus on performance; first, confirm whether the material can clean the surface in your mold set.

Keep two samples, mark the batch number, drying parameters, and mold temperature, and keep them at least until the end of the second round.

Second round · Process window: fix the material, adjust mold temperature, and make two sets of comparison parts for gate arrangement.

Check the flatness of the assembly surface, gloss and color palette comparison, and short-shot filling.

The parameters output in this round are the parameters for subsequent mass production; The component splitting plan must finalize the fit between the panel and the frame during this round.

Retain samples by batch sealing, at least three months after mass production stabilizes.

Third round · Aging and complete machine: Perform xenon lamp aging according to cumulative energy, retest color difference and mechanical retention; After aging, add one more round of flame retardant and wet electric marking; Then install on the pile to run for rain exposure and seasonal re-inspection.

Only after this round is recommended to ramp up.

Sample retention and sealing cycle covers the first batch of production, making it easier to trace the cause.

9. Self-Production Capacity and FAQs

The additive system in the formula is tailored according to the working conditions of each piece—regular additives are always in stock, special models are matched as needed; You report the working conditions and grade, and the materials and additives are all prepared in one go.

If you want to use this article for a report, you can summarize it in four lines:

ItemOne-sentence conclusion
What to replacePile shell and gun shell separately, first set the weather resistance rating based on outdoor conditions
What to moveRearrange mold temperature gates, dry replace with dehumidification, Re-defining tolerances on the assembly surface
What to testXenon lamp color difference and retention, wet electro-trace formation, flame retardancy after aging, low-temperature shock
When will volume increaseThree rounds of mold trials, no degradation after retesting, no abnormalities during seasonal inspection of the whole machine

Three frequently asked questions by readers

Question: After adding weather-resistant modification, why is it still yellow? You need to see if other systems have squeezed out the share after adding it, and also check if the processing temperature has consumed it in advance.

Question: Should the electric mark formation and flame retardant of the pile body be retested after aging? Yes. Both of these items depend on the surface condition; factory passing does not mean passing the test years later.

Q: Can the gun shell and pile body be made of the same material? Most projects do not recommend it. The requirements for the two parts are opposite; usually both sides are barely made of the same material.

Make your situation clear first, then negotiate the price.

For some orders, we'd rather say "our material isn't suitable for this piece" than take it rigidly. If you choose the wrong model, cheap can be expensive.

The three follow-up questions at the beginning—asking if it's the pile body or the gun shell, the accumulated energy of weathering, and whether it was retested after aging—once you get back to this, it's clear: if all three are answered, should the shell be split or assembled, and which items to re-inspect after replacement, it's basically decided

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