46-phi cylindrical cells are a multi-form-factor product line with a fixed 46mm diameter and variable heights of 4680, 4695, 46100, and 46120. LG Energy Solution began mass production of 4695 (46mm×95mm) at its Ochang plant, and Samsung SDI has also unveiled 4 variants at its Cheonan plant, mass-producing 4695 first for initial supply to a US customer.
Problem Definition
The decision to produce cells of multiple heights on one line creates a mechanical contradiction. The crimping head and winding mandrel use the Z-axis position referenced to the can opening as the datum plane. While the diameter is common, once height varies from 80 to 120mm, the crimping down-stroke, gasket compression position, and welding-head insertion depth all change. Should the entire jig set be replaced, or should only a height-adjustment sleeve be swapped on a common base?
Kinematic Analysis
The load-transfer path of can assembly runs crimping roller → can-top grooving section → gasket compression surface, in that order. Because the datum is the opening at the top rather than the can bottom, clamping products of different heights on the same lower jig misaligns the compression depth. A fully separate jig per product eliminates datum-plane error but increases setup time; a common base + sleeve reduces setup time but leaves sleeve-tolerance stack-up as residual error.
Calculation / Formula Verification
First, find the crimping compression force. With target surface pressure $p$, contact width $w$, and can circumference $L$, the required compression force $F$ is as follows.
$$F = p \times w \times L,\quad L = \pi \times D$$
Substituting diameter $D=46$mm, contact width $w=1.2$mm, and target surface pressure $p=15$MPa (estimated based on gasket compression ratio — confirm after field measurement) gives $L=144.5$mm, $F \approx 2{,}601\text{N} = 2.6\text{kN}$. Because the diameter is common, this value holds regardless of form factor.
The safety factor is dually verified. The primary check is the allowable load of the crimping-roller shaft. With shaft diameter $d=12$mm, SCM440 yield strength $\sigma_y=590$MPa (material certificate unconfirmed — confirm against field test report), cross-sectional area $A=113\text{mm}^2$, and $SF=2$ applied, the allowable load is as follows.
$$F_{allow} = \frac{\sigma_y \times A}{SF} = \frac{590 \times 113}{2} \approx 33{,}335\text{N}$$
Against the required compression force of 2.6kN, the margin ratio is 12.8×, an over-designed region. The secondary check is can-body buckling. A thin cylinder with can thickness $t=0.3$mm (estimated) and radius $r=23$mm has local buckling margin as the actual bottleneck when subjected to crimping reaction force. Determining the safety factor from the shaft allowable load alone can miss the can buckling limit, so the lower of the two safety factors governs the design.
Shop-notes
The common-base + height-adjustment-sleeve approach is adopted as Option 1. Since the compression force is constant regardless of form factor, the crimping head is standardized while only the sleeve is prepared per product. The alternative of a fully separate jig set per product reduces error but was not adopted, since line downtime increases with every changeover. Machinability note: the sleeve-fastening interface should be designed with a key rather than an interference fit. A tapered interference fit demands higher precision, making tolerance repeatability difficult on general-purpose CNC lathes.
Design-Reflection Checklist
Sleeve locating-key tolerance held to h7; can-material yield strength reconfirmed against field test report; measured crimping compression force cross-checked against the calculated value (2.6kN); re-verify whether the can buckling safety factor is lower than the shaft allowable-load safety factor.
One-Line Summary
Because the 46-phi multi-form-factor line has a fixed diameter, crimping compression force can be standardized, but the difference in height datum must be absorbed with a sleeve-changeable jig to protect the buckling safety factor.