[{"data":1,"prerenderedAt":418},["ShallowReactive",2],{"post-en-guides-router-bit-geometry":3,"header-article-translation-en-guides-router-bit-geometry":232,"trans-guides-router-bit-geometry-en":233},{"id":4,"title":5,"body":6,"category":201,"date":202,"description":203,"difficulty":204,"draft":205,"duration":206,"extension":207,"featured":205,"image":208,"layout":212,"locale":213,"meta":214,"navigation":215,"path":216,"references":217,"related":225,"section":226,"seo":227,"slug":228,"status":225,"stem":229,"tags":225,"translationKey":230,"updated":225,"video":225,"__hash__":231},"content\u002Fen\u002Fguides\u002Frouter-bit-geometry.md","Choosing Router Bits by Flute Geometry",{"type":7,"value":8,"toc":191},"minimark",[9,18,23,26,36,92,98,101,105,108,113,116,120,123,126,131,135,138,141,146,150,153,156,161,165,188],[10,11,14],"cnc-warning",{"level":12,"title":13},"warning","Selection principles, not a machine-specific guarantee",[15,16,17],"p",{},"The relationships below help you choose a starting cutter. They do not replace the tool maker's data, the machine manual, or a scrap-material test. Verify the shank, cutting length, collet, material, workholding, and clearance before a real cut.",[19,20,22],"h2",{"id":21},"start-with-the-edge-and-chip-problem","Start with the edge and chip problem",[15,24,25],{},"Router bits are easier to choose when you begin with the result you need rather than the name on the package. Ask two questions:",[27,28,29,33],"ol",{},[30,31,32],"li",{},"Which surface needs the cleanest edge?",[30,34,35],{},"Where must the chips go so they do not pack, recut, or overheat the cut?",[37,38,39,55],"table",{},[40,41,42],"thead",{},[43,44,45,49,52],"tr",{},[46,47,48],"th",{},"Geometry",[46,50,51],{},"Typical effect",[46,53,54],{},"Trade-off to check",[56,57,58,70,81],"tbody",{},[43,59,60,64,67],{},[61,62,63],"td",{},"Up-cut spiral",[61,65,66],{},"Lifts chips out of the cut and usually improves chip evacuation",[61,68,69],{},"The top edge may show more fuzz or tear-out; chips need extraction",[43,71,72,75,78],{},[61,73,74],{},"Down-cut spiral",[61,76,77],{},"Pushes chips toward the workpiece and can improve the visible top edge",[61,79,80],{},"Chips can collect in a pocket or blind slot and may be recut",[43,82,83,86,89],{},[61,84,85],{},"Compression spiral",[61,87,88],{},"Combines up-cut and down-cut sections for two-sided sheet work",[61,90,91],{},"The result depends on cut depth; a shallow pass may not engage the compression section",[93,94],"figure",{"alt":95,"caption":96,"src":97},"Schematic of an up-cut router bit lifting chips from a workpiece","Schematic: an up-cut spiral lifts chips; actual edge quality also depends on grain, support, and cutting parameters.","\u002Fmedia\u002Fdiagrams\u002Ftooling\u002Frouter-bit-geometry-upcut-chip-direction.svg",[15,99,100],{},"Do not interpret “up-cut” or “down-cut” as a quality ranking. They are different chip-flow choices. In a pocket, a down-cut tool can make a clean top edge while leaving chips in the pocket. In a through-cut, an up-cut tool may evacuate chips better while increasing top-edge fuzz. The correct choice depends on which trade-off your operation can accept.",[19,102,104],{"id":103},"when-compression-geometry-is-appropriate","When compression geometry is appropriate",[15,106,107],{},"A compression bit is useful when both the top and bottom faces of a laminated sheet need edge control. It only works as intended when the toolpath reaches the part of the cutter where the opposing flute directions overlap the material. Follow the tool maker's recommended minimum engagement and do not assume that one shallow pass will produce a compression cut.",[93,109],{"alt":110,"caption":111,"src":112},"Schematic of a compression router bit with opposing flute directions","Schematic: compression geometry combines opposing flute directions; the required cutting depth is tool-specific.","\u002Fmedia\u002Fdiagrams\u002Ftooling\u002Frouter-bit-geometry-compression.svg",[15,114,115],{},"For ordinary plywood or MDF, start with the simplest geometry that solves the edge problem. A compression cutter is not automatically better, and a more complex cutter may make chip evacuation and parameter selection harder.",[19,117,119],{"id":118},"use-flute-count-as-a-constraint-not-a-score","Use flute count as a constraint, not a score",[15,121,122],{},"Flute count changes the available chip space and the relationship between feed rate, RPM, and chip load. A single-flute tool may provide more room for chips when the machine and material support it. A two-flute tool is a common woodworking starting point. Higher flute counts can suit particular finishing or material-removal strategies, but they also change the required feed and chip-clearance behavior.",[15,124,125],{},"Never copy a feed value from a different flute count. Use the formula and tool maker's chart for the actual tool, then validate on scrap.",[93,127],{"alt":128,"caption":129,"src":130},"Two-flute up-cut router bit with a spiral cutting edge","A two-flute cutter is a common woodworking starting point, not a universal default for every material or machine.","\u002Fmedia\u002Fdiagrams\u002Ftooling\u002Frouter-bit-geometry-upcut.svg",[19,132,134],{"id":133},"prefer-the-shortest-cutter-that-reaches-the-job","Prefer the shortest cutter that reaches the job",[15,136,137],{},"Longer cutting length increases reach but usually reduces rigidity. A “three times diameter” relationship can be used as a warning boundary in early tool selection, not as a universal safety limit. Tool material, shank diameter, stickout, machine rigidity, radial engagement, and feed all affect deflection.",[15,139,140],{},"Choose enough cutting length to clear the workpiece and no more. Keep the stickout as short as the collet and workholding allow, and verify that the collet grips the shank rather than the flutes.",[93,142],{"alt":143,"caption":144,"src":145},"Schematic showing a long cutter deflecting under cutting load","Schematic: increasing unsupported length increases deflection risk; the exact limit depends on the complete setup.","\u002Fmedia\u002Fdiagrams\u002Ftooling\u002Frouter-bit-geometry-flute-length.svg",[19,147,149],{"id":148},"separate-roughing-from-finishing","Separate roughing from finishing",[15,151,152],{},"The cutter that removes most of the material does not have to establish the final dimension. A roughing pass can leave a small, deliberate allowance. A finishing pass can then remove that allowance with a lower engagement and a more predictable edge.",[15,154,155],{},"This strategy is useful when dimensional accuracy or visible edge quality matters, but it does not remove the need for workholding, toolpath simulation, and a test cut.",[93,157],{"alt":158,"caption":159,"src":160},"Schematic of roughing passes leaving a small allowance for a finishing pass","Schematic: a finishing pass can establish the final boundary after roughing removes the bulk of the material.","\u002Fmedia\u002Fdiagrams\u002Ftooling\u002Frouter-bit-geometry-roughing-finishing.svg",[19,162,164],{"id":163},"a-repeatable-selection-checklist","A repeatable selection checklist",[27,166,167,170,173,176,179,182,185],{},[30,168,169],{},"Identify the material, thickness, visible faces, and whether the operation is a pocket, profile, or through-cut.",[30,171,172],{},"Select the chip direction that matches the edge and evacuation requirement.",[30,174,175],{},"Confirm the cutter diameter, flute count, cutting length, shank, and manufacturer limits.",[30,177,178],{},"Use the shortest practical cutting length and the minimum stickout that still clears the work.",[30,180,181],{},"Set a conservative toolpath, simulate it, and verify clamps and clearance.",[30,183,184],{},"Run a shallow test in matching scrap and inspect chips, sound, edge quality, and movement.",[30,186,187],{},"Change one variable at a time and record the actual tool, material, and result.",[15,189,190],{},"The best bit is not the most advanced one. It is the simplest geometry that satisfies the edge, chip-flow, reach, and rigidity requirements of the operation you can verify.",{"title":192,"searchDepth":193,"depth":193,"links":194},"",2,[195,196,197,198,199,200],{"id":21,"depth":193,"text":22},{"id":103,"depth":193,"text":104},{"id":118,"depth":193,"text":119},{"id":133,"depth":193,"text":134},{"id":148,"depth":193,"text":149},{"id":163,"depth":193,"text":164},"Tooling","2026-09-09","A practical guide to up-cut, down-cut, compression, flute count, and cutter rigidity for desktop CNC routing.","beginner",false,8,"md",{"src":209,"alt":210,"caption":211},"\u002Fmedia\u002Farticle-covers\u002Fguides\u002Frouter-bit-geometry.webp","Three unbranded router bits on a workbench beside a desktop CNC router","Editorial cover image; the bit arrangement is illustrative, not a tool specification.","article","en",{},true,"\u002Fen\u002Fguides\u002Frouter-bit-geometry",[218,222],{"id":219,"title":220,"url":221},"onsrud-routing-tools-catalog","LMT Onsrud Production Cutting Tools Catalog","https:\u002F\u002Fwww.onsrud.com\u002Fimages\u002F2017%20LMT%20Onsrud%20Production%20Cutting%20Tools%20Catalog.pdf",{"id":223,"title":224},"laetoly-cam-toolpath-basics","Laetoly CAM Toolpath Planning & Conservative Feeds",null,"guides",{"title":5,"description":203},"router-bit-geometry","en\u002Fguides\u002Frouter-bit-geometry","guides-router-bit-geometry","cDT8ubw92RoK6j_jGGkVj1EIhOIQTT-p_kaYs0W_kBk",{"section":226,"slug":228},{"id":234,"title":235,"body":236,"category":201,"date":202,"description":405,"difficulty":204,"draft":205,"duration":206,"extension":207,"featured":205,"image":406,"layout":212,"locale":409,"meta":410,"navigation":215,"path":411,"references":412,"related":225,"section":226,"seo":415,"slug":228,"status":225,"stem":416,"tags":225,"translationKey":230,"updated":225,"video":225,"__hash__":417},"content\u002Fzh\u002Fguides\u002Frouter-bit-geometry.md","如何根据刀具几何形状选择 CNC 铣刀",{"type":7,"value":237,"toc":397},[238,244,247,250,258,308,312,315,318,321,325,328,332,335,338,342,345,348,351,355,358,361,364,368,371,394],[10,239,241],{"level":12,"title":240},"这是选刀原则，不是针对某台机器的安全保证",[15,242,243],{},"下面的关系用于确定起始刀具，不能替代刀具厂商数据、机器手册和废料试切。正式切削前，请确认刀柄、刃长、夹头、材料、夹持、路径和安全高度。",[19,245,246],{"id":246},"先明确边缘和排屑问题",[15,248,249],{},"选择铣刀时，不要先看包装上的名称，而应先明确最终结果：",[27,251,252,255],{},[30,253,254],{},"哪个表面需要最干净的边缘？",[30,256,257],{},"切屑应该往哪里排出，才能避免堆积、重复切削或过热？",[37,259,260,273],{},[40,261,262],{},[43,263,264,267,270],{},[46,265,266],{},"几何形状",[46,268,269],{},"通常效果",[46,271,272],{},"需要检查的取舍",[56,274,275,286,297],{},[43,276,277,280,283],{},[61,278,279],{},"上切螺旋",[61,281,282],{},"将切屑向上带出，通常有利于排屑",[61,284,285],{},"上表面可能出现更多毛刺或撕裂，需要良好吸尘",[43,287,288,291,294],{},[61,289,290],{},"下切螺旋",[61,292,293],{},"将切屑压向工件，可能改善可见上边缘",[61,295,296],{},"盲槽或型腔中的切屑可能堆积并被重复切削",[43,298,299,302,305],{},[61,300,301],{},"压缩螺旋",[61,303,304],{},"组合相反的刃向，用于控制板材上下边缘",[61,306,307],{},"取决于切削深度；浅层切削可能没有进入压缩区域",[93,309],{"alt":310,"caption":311,"src":97},"上切铣刀将切屑带离工件的示意图","示意图：上切螺旋会将切屑向上带出；实际边缘质量还取决于木纹、支撑和切削参数。",[15,313,314],{},"不要把“上切”和“下切”理解成质量排名。它们只是不同的排屑选择。型腔中下切刀可能带来更干净的上边缘，但也可能让切屑留在型腔中；贯穿切削中上切刀可能更利于排屑，但会增加上边缘毛刺。最终选择取决于当前工序能接受哪一种取舍。",[19,316,317],{"id":317},"什么时候使用压缩刀",[15,319,320],{},"当覆膜板或胶合板的上下表面都需要控制边缘时，压缩刀可能有价值。它只有在切削深度进入刀具设计的重叠区域时，才能产生预期效果。必须遵守刀具厂商给出的最小啮合深度，不要假设一次浅层切削就能实现压缩切削。",[93,322],{"alt":323,"caption":324,"src":112},"上下刃向相反的压缩铣刀示意图","示意图：压缩几何组合了相反刃向，所需切削深度取决于具体刀具。",[15,326,327],{},"对于普通胶合板或 MDF，优先选择能够解决边缘问题的简单几何形状。压缩刀并不自动更好，复杂刀具也可能增加排屑和参数调整难度。",[19,329,331],{"id":330},"把刃数当作约束而不是评分","把刃数当作约束，而不是评分",[15,333,334],{},"刃数会改变排屑空间，以及进给、转速和每齿切屑厚度之间的关系。单刃刀在某些材料和机器条件下可以提供更大的排屑空间；双刃刀是木工场景中常见的起点；更多刃数则可能适合特定的精加工或材料去除策略，但也会改变所需进给和排屑条件。",[15,336,337],{},"不要把某种刃数的进给值复制给另一种刃数。应根据实际刀具使用公式和厂商表格，再通过废料验证。",[93,339],{"alt":340,"caption":341,"src":130},"带螺旋刃的双刃上切铣刀示意图","双刃刀是常见木工起点，但不是所有材料和机器的通用默认值。",[19,343,344],{"id":344},"优先选择刚好够用的最短刀具",[15,346,347],{},"更长的刃长可以增加可达深度，但通常会降低刚性。“刃长约为直径三倍”可以作为早期选刀时的警戒线，不能当作通用安全上限。刀具材料、刀柄直径、伸出长度、机器刚性、径向啮合量和进给都会影响挠曲。",[15,349,350],{},"选择足以穿过工件的刃长即可，不要额外追求长刃。伸出长度应尽可能短，并确认夹头夹住的是刀柄而不是刃部。",[93,352],{"alt":353,"caption":354,"src":145},"长刃铣刀在切削力下发生挠曲的示意图","示意图：未支撑长度越长，挠曲风险越高；实际限制取决于完整加工条件。",[19,356,357],{"id":357},"将粗加工和精加工分开",[15,359,360],{},"负责去除大部分材料的刀具，不必同时建立最终尺寸。粗加工可以有意留出少量余量，再用更小啮合量的精加工清除余量，从而获得更可预测的边缘和尺寸。",[15,362,363],{},"这对尺寸精度和可见边缘很有帮助，但不能替代夹持检查、刀路模拟和废料试切。",[93,365],{"alt":366,"caption":367,"src":160},"粗加工留下余量并由精加工建立最终边界的示意图","示意图：粗加工去除大部分材料，精加工负责建立最终边界。",[19,369,370],{"id":370},"可重复执行的选刀清单",[27,372,373,376,379,382,385,388,391],{},[30,374,375],{},"明确材料、厚度、可见表面，以及工序是型腔、轮廓还是贯穿切削。",[30,377,378],{},"根据边缘和排屑要求选择刃向。",[30,380,381],{},"核对刀具直径、刃数、刃长、刀柄和厂商限制。",[30,383,384],{},"选择刚好够用的刃长，并让伸出长度尽可能短。",[30,386,387],{},"设置保守刀路，完成模拟并检查夹具和安全高度。",[30,389,390],{},"在相同材料的废料上进行浅层试切，观察切屑、声音、边缘和工件移动。",[30,392,393],{},"一次只改变一个变量，并记录实际刀具、材料和结果。",[15,395,396],{},"最好的刀具不是最复杂的刀具，而是能够满足当前边缘、排屑、可达深度和刚性要求，并且可以通过试切验证的最简单方案。",{"title":192,"searchDepth":193,"depth":193,"links":398},[399,400,401,402,403,404],{"id":246,"depth":193,"text":246},{"id":317,"depth":193,"text":317},{"id":330,"depth":193,"text":331},{"id":344,"depth":193,"text":344},{"id":357,"depth":193,"text":357},{"id":370,"depth":193,"text":370},"从上切、下切、压缩刀、刃数和刀具刚性出发，为桌面 CNC 路由选择合适的刀具。",{"src":209,"alt":407,"caption":408},"桌面 CNC 旁工作台上的三把无品牌螺旋铣刀","文章封面示意图；刀具排列不代表具体刀具规格。","zh",{},"\u002Fzh\u002Fguides\u002Frouter-bit-geometry",[413,414],{"id":219,"title":220,"url":221},{"id":223,"title":224},{"title":235,"description":405},"zh\u002Fguides\u002Frouter-bit-geometry","kq1B4j8X9fWqwMjOJehnORxi3KmHrWWSvsY443unfEI",1789009347394]