Advanced Machining Flashcards
Typical parts
Parts with complex cavity and or small diameter holes
Why we need advanced machining processes
- workpiece material too brittle for conventional machining processes
- Workpiece is too flexible
- Shape of part is too complex
- heat of tool and workpiece is too high with conventional maching
Chemical Milling/Machining
- Metal is dissolved with a chemical etchant
- parts that are not supposed to dissolve can be covered with wax/mask
What is undercut?
happens with chemical machining: at the edge of mask material will be dissolved even though its not supposed to come off
Advantages/Disadvantages Chemical Milling
Advantages: -Low capital cost once equipment is set -work surfaces can be done simultaniously -no cutting forces /thermal stress Disadvantages: -Undercutting -Sharp corners not possible -workpiece material must be homogenous -environmental issues -dessolving might be not equally
Chemical Blanking
Similar to Sheet metal blanking but material is blanked by chemical dissolution rather than shearing
Electrochemical Machining
similar to chemical machining but dissolution goes way faster
Advantages/disadvantages electrochemical Machining
Advantages: -any material can be cut -no cutting forces/thermal stress -long tool life -no egde burrs Disadvantages: -Workpiece must be conductive -equipment expensive & high tooling cost
Electrical Discharge Machining
Metal removed by intense heat of sparks (no chemicals used)
finishing and roughing possible
Workpiece and Tool are submerged in dielectric fluid (mineral oil)
at low voltage the fluid works as a isolator
as voltage increases the sparks passes between gap of tool and workpiece; spark vaporizes material from both workpiece and tool
-slow process
Wire EDM
- Sharp corners possible
Advantages/Disadvanages EDM
Advantages: - material of any hardness can be cut - high accuracy -no cutting forces/thermal stress Disadvantages: -Workpiece musst be conductive -slow process -heat effected zone near cutting edges
Laser Beam Machining
-high energy cutting process where the material is melted/vaporized by a narrow beam of coherent light
Facts Laser Beam Machining
Produces small precision cuts leaves rough material surface heat affected zone narrow to cut has good repeatability not only 2D but also 3D (calculate it doesnt cut through the whole piece)
Water Jet cutting
thicker pieces than laser cutting possible; food processing because more hygienic
Abrasiven Jet (water) cutting
deeper holes; harder materials
