From: Deak, Steve (US EL) (email@example.com)
Date: Tue Oct 15 2002 - 16:18:15 EEST
Standard bead blasting of SL parts uses dry media, usually glass bead, and compressed air (35-60 psig). At best, this method "frosts" the macro surface and blends sanded areas to a uniform appearance. This method does not remove stair-stepping. Cost for a dry unit ranges from USD$750.00 to USD$2000.00.
"Wet Blasting" creates a far better surface finish for SL models, perhaps what you are referring to. Wet blasting uses glass and/or aluminum oxide media in a wet slurry. The slurry is pumped through the blast gun at relatively low pressure. Compressed air (50-80 psig) is then used to propel the slurry, creating an incredible satin finish very quickly. This method can also be very aggressive. Great care must be taken selecting media, pressures and techniques. All your "built-in" RP accuracy can go out the window with a few flicks of the wrist.
Wet blasting has many advantages over dry blasting. First, a higher quality, satin surface finish. There is no static electricity generated (this is a big problem with dry blasters....ever get shocked?). Thirdly, there is no particulate dust outside the blaster.
A unit I would recommend is the Zero BNP-250 (size: 36x by 36y by 37z inches). This is a recirculating unit, meaning the media gets used over and over again. Some systems discharge the media after 1 cycle through the blast gun. The Zero BNP-250 also has an exhaust fan, requiring no outside ducting. Utilities needed are electricity (lights and fan), water (washing the viewing window, filling slurry tank) and compressed air. No dust collector required. This unit sells for USD$7500.00, so the cost is substantial, but worth it. maintenance on a unit like this entails rebuilding the slurry pump every 1-2 months. The valve seats are made of nylon and are readily replaceable.
A contact would be Dale Seigle, A&B Deburring, Cincinnati, OH (+1) 513.723.0444. firstname.lastname@example.org.
I do not get paid for this endorsement and have no relatives working at the company. I have, however, used this exact unit with great success.
Mgr-SL Field Support
4917 Dawn Avenue
East Lansing, MI 48823
From: ebunch [mailto:email@example.com]
Sent: Tuesday, October 15, 2002 7:57 AM
Subject: Bead Blasting SLA parts
I was wondering if anyone has ever heard of bead blasting SLA parts to a pattern finish. If so, could you please explain the process as far as the blasting media and any special procedures necessary? Thank you for your input.
Phone (248) 852-6250 x 119
Fax (248) 852-4139
For more information about the rp-ml, see http://rapid.lpt.fi/rp-ml/
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