2 Sided Machining a Native American Flute

Our lofty goal was to have a precision blank that could be made on our CNC machine that could then be personalized on the lathe or however the student saw fit.  The problem with the blanks available is that they are fairly expensive, not customizable and the precision I was most interested in is the hole placement.  Blanks available are not already drilled for holes.  We were not aiming for a finished flute, but I wanted a proof of concept that the Slow air chamber and flute parts work, so we designed a working prototype that is actually a finished flute.  It would be easier to test a finished product.  The first test worked perfectly and the sound quality is superb, but it is royally out of tune and we are working as a class to devise a plan to create a prototype that we can move and individually tune specific holes.  With this prototype we will be able to plan each individual note and customize each student’s flute to the desired key and scale desired.

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T-slot CNC table hold downs

 

Holding things down on a CNC can be the most frustrating part of the entire process.  Luckily for us our main machine has a vacuum table and we use window sealant foam for the back of the wood.  This works amazingly well for parts that are not cut through.  We have had to get creative for parts that need cutting all the way through.  Our large machine has an MDF table that has T-Slots cut into it and it requires hold downs.  I have seen all sorts of solutions for this, but few solved my main concern of wanting to carve on the entire board unhindered by the hold downs.

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Brazing with the Acetylene ‘B’ tank

Getting going with the oxygen/acetylene torch can be both exciting and overwhelming.  It is kinda like learning to drive and learning how to operate a manual transmission.  You have to focus on the rules of the road and do a great job driving while at the same time learning about the clutch.  It also reminds me of learning to ride a bike.  You have to learn to balance and pedal at the same time.  If we break these down into individual lessons we can focus on the getting the required skills to move up.  In this case I find students overwhelmed with 2 tanks, managing pressures, using a large torch and making great welds at the same time.  I brought in this little ‘B’ tank to help with most of that.  The ‘B’ tank only uses an acetylene tank and grabs air from the room rather than an oxygen tank.  The advantage is easy starting.  The disadvantage is a huge reduction in heat.    The ‘B’ tank will only be useful for brazing, but it’s main purpose is to teach the skills necessary to be successful with the oxygen/acetylene torch.

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Depth of a V-Carve in Aspire

The V-Carve will likely be your first CNC created file.  The software does a great deal of the work and creates beautiful carves from fairly complicated designs.  Once your design is in vector form, you are ready to create a V-Carve toolpath.  It is important to understand what the software is doing for you and how it decides the depths of cut that were made.  In the simplest mathematical terms:

The depth of cut is a function of the distance between vectors and angle of chosen V-Bit.

Lets break that down a bit…

This design is what I am bringing into aspire.  This could be a font, design, scan, shapes, etc.

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Plasma cutting setup and speeds (and other data).

Take this data over with you to the Hypertherm Powermax 65 Plasma cutter.  This works with the CNC and the hand torch.  I got this from the Hypertherm Powermax 65 manual (click for the actual manual).  Some of the data is not needed for the hand torch, but needs to be inputed into the CNC controller.

1. You will need to choose your setup of Shielded (for us this is Hand) or UnShielded (for us this is CNC).

2. Choose your amperage 45 or 65 (Mostly you will do 65Amps) or if you want to use FineCut.

3. Setup the torch with the desired consumables and choose your chart link below for access to the speeds, volts height pierce delay and pierce height.

4. Manage your Kerf thickness with this chart

65 amps by hand (this is your default setup for hand plasma)

65 amp shielded setup

45 amps by hand

45 amp  shielded setup

FineCut by hand or CNC

fine cut setup

65 amps on the CNC (this is your default setup on the CNC)

65 amp unsheilded setup

45 amps on the CNC

45 unshield setup