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| author | nathan <nathan@nathan-VirtualBox.(none)> | 2012-08-01 23:56:11 -0400 |
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| committer | nathan <nathan@nathan-VirtualBox.(none)> | 2012-08-01 23:56:11 -0400 |
| commit | 4bd17c3fdf8f339385e406add6806be45655eb1e (patch) | |
| tree | e515619a8847c52ad30f9079e30ce1ee1aea93fd | |
| parent | c2c787e12d81ebec91189e5d177ac8f65d7f72c0 (diff) | |
| download | laser_etcher-4bd17c3fdf8f339385e406add6806be45655eb1e.tar.gz laser_etcher-4bd17c3fdf8f339385e406add6806be45655eb1e.zip | |
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| -rw-r--r-- | laser_etcher | 78 |
1 files changed, 78 insertions, 0 deletions
diff --git a/laser_etcher b/laser_etcher new file mode 100644 index 0000000..a9595be --- /dev/null +++ b/laser_etcher @@ -0,0 +1,78 @@ +parts procurement +---------------- + +Spreadsheet here: https://docs.google.com/spreadsheet/ccc?key=0AkTsdtdxo56DdFVYWkd4YjhKVmdfSk1WV1ZpZ2F5enc + +gantry: + rail, 1, $99.00 http://www.vxb.com/Merchant2/merchant.mvc?Screen=PROD&Store_Code=bearings&Product_Code=Kit8279&Category_Code=12mmLinearMotionSystems + trucks, 6, $9.95, http://www.vxb.com/Merchant2/merchant.mvc?Screen=PROD&Store_Code=bearings&Product_Code=Kit8512&Category_Code=12mmLinearMotionSystems + thrust bearing 8mm ID x2, 2, $14, http://www.vxb.com/page/bearings/PROD/Thrust/Kit7153 + ball bearing 8mm ID 16mm OD, 2, $1, http://www.vxb.com/page/bearings/PROD/8mm/688ZZ-1 + bearing block, 2, $10, http://www.vxb.com/page/bearings/PROD/kit7136 + 3/8-40 acme wear-compensating nut, 2, $35.03, mcmaster 6350K213 + 3/8-40 acme threaded rod, 1, $157.36, mcmaster 6350K137 + + spring washer (wave washer, for thrust bearing preload), 2, + helical coupler, 2, + stepper, 2, + +laser: + test Blu-Ray 12X BD-R drive, contains at least 700mW 405nm laser $100 newegg + + if that works, try replacing the diode with 1W version from ebay (or 2W 445nm laser), custom beam expander and may be required but should be pretty cheap and easy + + +design +------ + +bearings are needed to prevent the screw from whipping around, as it will be rotating at about 1000rpm. instead of +making bearing blocks we can(?) buy shaft holders from vxb, sized to fit the OD of the bearing. then, two thrust +bearings go on either side of the shaft block, constraining the leadscrew in the axial direction. the leadscrew ends +are machined to have a shoulder and a capture nut. the stepper motor drives the other end of the screw with a helical +coupler or diaphragm joint and prevents it from whipping around. (?) + +kinematic design to prevent binding and flexing. each axis has 3 trucks, 2 on one rail, 1 on the other rail. + + +grouted construction (moglice epoxy to bed components) + +shims to align components vertically + +granite or mic-6 plate, as most convenient + + + +optics calculations +------------------- + +referencing the paper "Characterization of Program Controlled CO2 Laser-Cut PDMS +Channels for Lab-on-a-chip Applications", available from the publisher and at +http://fennetic.net/irc/laser_ablation_profile_power.pdf + +fig.7 in the paper shows a full-depth (trapezoidal) channel, cut at "25% speed" + +after searching through the paper for values because of the obnoxious lack of units in their graphs, we find the +parameters used to be: + +channel width: 700um +film thickness: 381um +laser wavelength: 10600nm +cutting speed: 254cm/s (wow!) +cutting power: 60W + +this works out to give a power density of 60W/(700micron*0.25*254cm/s) += 13.5 J/cm^2 +and assuming a full-depth cut, 60W/(381micron*700micron*0.25*254cm/s) += 354 J/cm^3 + + +optics equations/calculators +---------------------------- + +http://buildlog.net/cnc_laser/laser_calcs.htm +http://www.newport.com/Laser-Damage-Threshold/144932/1033/content.aspx + +optics links +------------ +CO2 +http://www.repairfaq.org/sam/laserco2.htm |