RE: [CAD_CAM_EDM_DRO] reality milling

Hi Tei,

Turbines are pretty cool. There are many different types. I would recommend starting with a simple one like in a vacuum cleaner or a compressor. This type of turbine can be built with a 2.5 or 3 axis mill.

Then you could get more complicated and build a gas turbine. This may require a 4 or 5 axis mill depending on the geometry. (I would wait until you have studied some differential equations and fluid dynamics before making a gas turbine... but maybe you'll find some plans that are easy to follow.)

As a reality check, I would recommend starting with some simpler projects and work your way up. If you are just learning about cutting metal, I would look at buying a lathe first. You'll save some money at the start and will develop your skills. Then get a 3 axis mill with an option to add a 4th axis. You'll appreciate having both a lathe and mill. If you are eager to get started, a 3 axis mill would be my first choice.

Before making your own turbine, I would suggest finding some existing ones to learn from. You may be able to purchase a gas turbine off the shelf at a hobby store - special ordered. But as I said earlier, I would start by taking apart a scrap vacuum cleaner and extract the turbine/motor. Build a shrowd to go around the turbine - for protection and to direct the flow down the center and then out the sides of the turbine. You could make the shrowd out of fiberglass - which is strong and can be patched. You'll learn alot by experimenting with an existing turbine. I would recommmend getting a variac to regulate the voltage/speed to the motor (if you use AC power to the universal motor that is likely in the vacuum cleaner) or if you choose to use a dc motor, get a variable dc power supply to regulate the voltage/speed. Don't fire it up to full speed/voltage without suitable protection around the turbine. A vacuum turbine with no load will likely turn at 25,000 to 40,000 RPM depending on the model of vacuum you salvage. With the airflow turbine like in a vacuum, you could also begin building your own pitot tubes and manometers for measuring the flow and pressure... You can probably find a simple description of the theory of an airflow turbine - the 'euler type turbine' - in a first course fluid dynamics text book for mechanical engineers. They model the system in 2D and the fluid is assummed to be non-compressible which should be easiest to follow. This is pretty close to the type of turbine used in the vacuum cleaner.

Darcy
-----Original Message-----
From: teilhardo [mailto:teilhardo@...]
Sent: Monday, June 16, 2003 5:36 PM
To: CAD_CAM_EDM_DRO@yahoogroups.com
Subject: [CAD_CAM_EDM_DRO] reality milling


hi,
my name is tei and I am an ambitious 17 year old without a lot of
money. I have been fascinated with turbines but the cost is to great
to buy them so I decided that the best way to get involved was to make
them. I have decided to buy some kind of cnc desktop mill or lathe
(sherline, maxnc, or taig) but i don't know if it can handle cutting
turbines and I don't have a clue how to even start on the task of
milling an impeller so I haven't had the courage to spend $1500 yet.
Can anyone give me any suggestions, hints or reality checks, I'd
really appreciate it.
Thank You



Addresses:
FAQ: http://www.ktmarketing.com/faq.html
FILES: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO/files/
Post Messages: CAD_CAM_EDM_DRO@yahoogroups.com

Subscribe: CAD_CAM_EDM_DRO-subscribe@yahoogroups.com
Unsubscribe: CAD_CAM_EDM_DRO-unsubscribe@yahoogroups.com
List owner: CAD_CAM_EDM_DRO-owner@yahoogroups.com, wanliker@..., timg@...
Moderator: pentam@... indigo_red@... [Moderators]
URL to this group: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO

OFF Topic POSTS: General Machining
If you wish to post on unlimited OT subjects goto: aol://5863:126/rec.crafts.metalworking or go thru Google.com to reach it if you have trouble.
http://www.metalworking.com/news_servers.html

http://groups.yahoo.com/group/jobshophomeshop I consider this to be a sister site to the CCED group, as many of the same members are there, for OT subjects, that are not allowed on the CCED list.

NOTICE: ALL POSTINGS TO THIS GROUP BECOME PUBLIC DOMAIN BY POSTING THEM. DON'T POST IF YOU CAN NOT ACCEPT THIS.....NO EXCEPTIONS........
bill
List Mom
List Owner



Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/