Design for Mill/Turning/Drilling - Massachusetts Institute of ...

Design for Mill/Turning/Drilling or how to save yourself or your machinist a lot of time and effort Overview

Drill Mill Lathe Surface Finish

Tips & Tricks Process Planning Drill Make a hold in something Drillpress OR hand-held drill Usually need clamps to hold part in place

Not highly accurate but often good enough A BIG distinction MANUAL machines vs. CNC machines A BIG distinction MANUAL machines vs. CNC machines

Lathes Manual CNC How do choose the correct machine? Round geometry

Axial alignment Flat/planar geometry Drill or Mill Lathe Axial and milled

geometry CNC Lathe With live tooling Odd (not circular) shapes Pockets, holes,

surface geometry CNC Mill Surface Finish Surface Finish

From 2.008 class notes, SP03 Surface Finish From 2.008 class notes, SP03 Tips & Tricks

For high precision, watch out for Overhanging geometry (deflection) Thin sections & tubes (vibration) Drilling incline planes For ease of manufacturing

Standard shape & size holes Proper tolerances (discussed tomorrow) Reference everything off one point

Avoid deep pockets & holes NO inside right edges! WATCH OUT for tool access! a short endmill used inside a deep narrow pocket might CRASH!) Dont cut into the vise or clamps! Mill: Part in Vise

To make it faster (& less annoying) Minimize number of fixtures Every time you take the part out of the vise you have to re-reference it wastes time! Include features for easy fixturing & referencing

Image from: http://www.wmccm.co.uk/WMCCM/DesktopDefault.aspx?tabindex=0&tabid=2049 Process Planning Process Planning From 2.008 Process Planning lecture, SP03

Process Planning TOMORROW Look for departmental resources

Machine shop resources Buy material Make material correct size

From 2.008 Process Planning lecture, SP03 Detailed Process Planning for Manufacturing Choose material and order it Make material correct starting size/shape Watch for tolerances when ordering parts arent always exact size or perfectly square

Plan what cuts/features to make first, second, third based on complexity, yield of process, etc. - SKETCH If something is likely to not work, dont do that step last! Detailed Process Planning for

Manufacturing, Continued Determine when to check for quality/accuracy in the process Easier to measure twice and cut once than the other way around! For any hand-machining operations, mark the parts in an OBVIOUS way!

ei, an X on the part that you dont want, scribble where you want material removed Optimizing your Process Plan Fewer steps = better Make a flowchart How Its Made Examples

Resources Machinerys Handbook

Manufacturing textbooks (Kalpakjian) Your local machinist MIT shops MIT departmental shops Edgerton Student Shop (on Vassar Street) MIT Hobby Shop