Twist-zoom lens barrel
Twist the ribbed grip and the inner tube glides out, like a camera lens. It was described in plain words in the Studio, not drawn: a body with straight keyways, a zoom ring split along its helical cam slot so both halves print with no supports and click together, a lens tube carried by three round pegs, a grip sleeve that hides the slots, and a snap-on cap. The checks cover what makes it work in the hand: the parts clear each other at both ends of the travel, the slot ends stop the tube, the cam is shallow enough to hold its zoom setting, and the snap fingers flex without cracking.
Ask for the sizes you want to tweak, e.g. “make the width adjustable”.
默认尺寸下的规格
在 Bambu Lab A1 上用 pla 实际构建测得。拖动上方滑块时，每个数字都会实时更新。
- 整体尺寸
- 74 × 74 × 60 mm
- 零件数
- 6
- 耗材
- 93 g
- 打印时间
- 2 h 46 min
- 打印盘
- 1
- 支撑
- 不需要
工程校验
校验和参数名称直接来自 CAD 引擎，以英文显示。
- Retracted: parts clearring/tube 0.00, body/tube 0.00, ring/body 0.00 mm³
- Extended: parts clearring/tube 0.00, body/tube 0.00 mm³ after 90° twist
- Half-way: parts clear0.00 mm³
- Slot ends stop the tubethe ring stops 2.7° past full zoom and 0.2° past fully retracted
- Ring halves seat cleanly-0.00 mm³ overlap; the tabs fill the joint zone so the halves turn as one
- Click travel is shorteach tab rides over its ridge for 2.8 mm, then drops into the groove
- Ring halves click together3 tabs 8.0 mm wide flex 0.35 mm over a ridge: 0.14% bend strain (PLA keep under ~1%)
- Ring half bands are solidlower band 5.9 mm, upper band 5.5 mm, post 2.0 mm thick
- Grip sleeve hides the spiral slotsone unbroken ribbed shell from z 6.1 to 41.5; 1.2 mm wall behind each keyway; overlaps 0.00 / 0.00 / 0.00 mm³
- Sleeve turns with the cam ring3 hidden keys 3 mm wide engage 1.0 mm into the sleeve
- Tube stays well guided when extended29.0 mm of tube still inside the body
- Lug reaches into the cam ring3.4 mm of each lug engages the spiral slot
- Pegs are round where they slideround from r 27.6 mm, ring starts at r 28.4 mm; root web stays inside the 28.2 mm body wall; slot hugs the peg with 0.3 mm play
- Holds its zoom settingcam slope 20.7°: the tube's weight can't spin the ring
- Cap seats with hooks in the groove0.00 mm³ overlap when clicked home
- Snap fingers flex without cracking0.95% bend strain over a 12.3 mm finger pushing over a 0.8 mm hook (PLA: keep under 1% for an occasional snap)
- Snap actually catches0.65 mm hook overlap past the body wall even with the cap pushed to one side
- Catch face holds against a pullhook top face is 18° off flat and seats under a matching ledge, so pulling up can't ramp it out
- Body wall left behind the groove2.1 mm of wall behind the catch groove
- Cap goes on last, over the lens tubecap hole 0.4 mm clear of the front bezel; 1.4 mm of lip sits on the body top
- Ring retained by cap0.3 mm end float under the cap
可调尺寸
| 设置 | 默认 | 范围 |
|---|---|---|
| Zoom travel | 18 mm | 10–22 mm |
| Twist angle | 90 ° | 70–90 ° |
| Ring play per side | 0.2 mm | 0.1–0.35 mm |
| Cap play per side (snap fingers hold it) | 0.15 mm | 0.05–0.3 mm |
零件清单
| 零件 | 数量 | 尺寸（mm） | 耗材 | 时间 |
|---|---|---|---|---|
| body | 1 | 70 × 70 × 51 | 24 g | 40 min |
| ring-lower | 1 | 65 × 65 × 32 | 9 g | 19 min |
| lens-tube | 1 | 58 × 58 × 56 | 20 g | 36 min |
| grip-sleeve | 1 | 74 × 74 × 35 | 21 g | 35 min |
| ring-upper | 1 | 65 × 65 × 32 | 9 g | 19 min |
| cap-ring | 1 | 70 × 70 × 11 | 9 g | 17 min |
制作方法
- Set the zoom travel and twist angle you like; the cam slot is recalculated.
- Print the parts as laid out: each one sits flat with its working face up.
- Click the two ring halves around the tube, slide on the grip sleeve, then snap the cap on last.
打印建议
- No supports. 0.2 mm layers with a 0.4 mm nozzle work well.
- If the ring feels tight or loose, change Ring play per side by 0.05 mm and reprint the ring only.
- Clear PETG shows the mechanism through the wall; PLA gives the crispest click.
常见问题
Was this really designed by describing it?
Yes. It started from one sentence, "I want a camera lens mechanism that you twist to extend or retract", and was refined in plain words: print without supports, make the pieces click together, hide the sliding mechanism.
Does it hold its position?
Yes. The cam slope is kept shallow, so the tube's weight cannot turn the ring by itself, and the slot ends stop it at both ends.
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