COMPLETE FABRICATION

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3. Aluminum Milling

Feeds, Speeds and Chipload Calculator: http://www.onsrud.com/xdoc/ChipAluminum

Aluminum cutting end mills from Onsrud: http://www.onsrud.com/xdoc/Metal-Cutting-Tools-And-Bits

OPTIMIZING SPEED AND FEEDS [can also find this infomation at http://www.onsrud.com/xDoc/MachFacts]

1. Start off using the recommended chipload and RPM for the material you are cutting.

2. Increase the feedrate until the part finish starts to decrease or you risk moving the part off the vacuum. Decrease the feed by 10%.

3. Next decrease your RPM by a set increment until your surface finish deteriorates again. Once this happens increase your RPM until the finish is acceptable.4. You have now optimized your speed and feed by taking the largest chip possible.
Note: This should be done in the first sheet of material to prevent tool dulling due to excessive heat.
TOOL HEATIf a feed rate is too low heat will be generated causing the cutting edge to break down and dull quickly. To check this, run a nest of parts and stop the spindle. When the spindle has stopped rotating, carefully feel the tool’s temperature. It should be at or near room temperature. If the tool is hot review “Optimizing Speed and Feeds”.

TOOL MATERIAL

• Solid Carbide: Primarily used in CNC operations. Material provides best rigidity and long tool life.

• Carbide Tipped: Incorporates the wear resistance of carbide and the toughness of a HSS body-mainly hand held.

• HSS: Primarily used in hand routing. Material provides a tough body and sharper cutting edge. Good in CNC.

FLUTE GEOMETRY

• Straight flute: Offers a neutral cutting action – highest force

• Upcut flute: Provides the best surface finish and allows for good chip extraction. May cause part lifting if vacuum or fixturing is not sufficient.• Downcut flute: Provides a downward force which helps eliminate part lifting. Chip rewelding MAY occur if there is no space below the part for chip expansion.

• Compression: Used for laminated materials, produces a good top and bottom finish on the part.

NUMBER OF FLUTES

• Single Flute: Allows for larger chiploads in softer materials

• Double Flute: Allows for better part finish in harder materials.

• Multiple Flutes: Allows for an even better part finish in harder materials.
Note: As the number of cutting edges increase, your feed rate should increase to prevent burning and premature tool dulling.

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4.196 Special Problems in Architectural Design Complete Fabrications Nick Gelpi Mon-Fri, Jan 5-7, 10-11, 13-14, 18, 20-21, 24-25, 27-28, 01-04:00pm, 3-402/7-432studio, 1st mtg Wed 1/5 Pre-register on WebSIS and attend first class. No listeners Prereq: Permission of instructor ; Yr-1 MArch students who have completed 4.123 only Level: H 9 units Standard A - F Grading Can be repeated for credit Lab Fee: 150 A comprehensive introduction to methods of “making” explored through a wide range of brief but focused exercises. Skills = developing complex geometries from flat components; fine-tuning press fit construction, molding and casting, and making repeatable molds for customization. A two-part workshop, the first half will contextualize contemporary tools and techniques within the trajectories of historical case studies of building, combined with hands on familiarization of tools. The second half will implement the tools of our workshop in the context of Design. Working on group design build process for three MIT 150 FAST installations, students will test and influencing designs through the instrumentality of production. These hands-on design build projects are intended to produce reciprocity between skills and design, making more complete the problems of fabrication. Subject limited to year-one MArch students who have completed core-1 studio. Contact: Nick Gelpi, 9-224, 253-9415, ngelpi@mit.edu -

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