Saturday, March 11, 2017

Six filaments no rotation.

Here is my work around of the gimble/rotater problem of getting all around coverage from the point source filaments.
So here is the set up. Six filaments. Front, back,top,bottom, left and right.
Wired in series
Powered from my chinese TIG welder.
And here are the filaments with the aluminium pressed on.
The system is running at 55v, which is the output voltage of the TIG. To get these really hot I'm right up at the limit of my TIG. I'm not sure what the current is.
This is the result...

Sunday, January 1, 2017

High Voltage plasma cleaning.

I was wondering if it was possible to have high voltage plasma in a conductive vacuum chamber?
Seems like it is!
My previous high voltage stuff had been in the glass belljar of previous posts.
So when I started reading about plasma cleaning and surface modification, it got me wondering. 
Here is the video: 

If you are still reading, some details are: The vacuum feedthrough is a 4mm brass rod through a 7mm glass tube. Soda glass I think. Not boro' anyway. Then the threaded bit is from an old lamp fitting. I did a little work on the lathe to make the o-ring groove. All sealed up with normal(not Kwik) JB Weld.

Then it gets pushed through one of the existing electrode holes in my base plate. I know the chamber is filthy...
Strangely, I got the best ever vacuum level from my mechanical pump on this test. I got down to nearly 2x10-2( chamber pressure) normally I only get 6 or 5x10-2. Just at the edge of diffusion pump land.

Some strange thing that happened were... 
Initally the pressure began to rise when I turned on the NST and so plasma. I'd unplug and let the pressure drop again. I did this about 5 times until gradually, the pressure stopped rising. Then I was able to leave the NST on for about 5mins or more. I didn't want to over heat the electrode.

Total in plasma was probably 10 mins at 150 watts.

In the video is some poor footage of the plasma exposed surface of some acrylic and the unexposed(I peeled the plastic film back after I took it out of the chamber). One wetting well, the other, no way!
As I handled it, the grease from my fingers was busily spreading from the sides of the acrylic across the surface. It was very interesting to see the contamination spread.

 Also possibly there was a good bit of oil from the saw blade used to cut this bit of acrylic.
The other sample in the chamber was a piece of fast cast polyurethane resin. It work on that too. Over all effect seems short lived. Maybe straight under Di-water is the thing to do.

Conclusion: yes it works. 
To do: clean the pieces normally to remove most of the contaminants. Wear gloves.
Try...spontaneous bonding of very clean flat surfaces by contact.

Tuesday, September 27, 2016

Evaporants arrival

Here is a small delivery from Midwest Tungsten Services.
I got some filaments, gold tone, bronze, and aluminium.
They were very nice to deal with. I spent 100dolla' to get these bits including shipping from the US to Ireland. 
I hope to try the Alu today.
 This form is called "cane" I suppose this is goldtone.

With some digging on the net I found it might be possible to evaporate "dutch leaf", as in, fake gold leaf. Seems to be a suitable alloy.

Tuesday, December 15, 2015

Huanyang Inverter VFD NC Studio Settings

I have been putting up non vacuum stuff up here for the last few posts because I have nowhere else to put them! The vacuum system is in stasis at the moment as other more daytoday things has been taking up my time. So my apologies to you high vacuumers out there.

This post is motivated by a day and a half of frustration which finally got sorted through much googling, testing, reading and rereading and logic-ing out. My cnc machine is now armed and fully operational! I have no doubt that there are others in the same position as I was yesterday...

Be warned: I am not an engineer and don't really know what I'm talking about here, so use this info at your own risk!

How I learned to love my new Huanyang VFD spindle for NC Studio. This post is just about getting NC Studio talking to the VFD, not motor settings. There are other good tuts out there on that bit.
I'll assume you've done a bit of work on this already and get right into the nitty gritty.

Please read it carefully, every step is important.

**some changes you make may need the VFD to be restarted, it seems...**

**with NC Studio we are dealing with '4-speed external control'. You don't really get the values in your gcode. boooo!**

Speed1 being stopped/no rotation. Defined by PD003/PD011(see below)
Speed2 definded by PD0086
Speed3 definded by PD0087
Speed4 defined by PD0088

To begin!
0.PD000 set to 0.  Allows changes to happen in the settings...

1. PD013 set to 8. Factory reset (Thus may not be nessasary if you have a matching VFD and spindle.)

2. PD001 set to 1. This selects external terminal/multi-input as the signal input.(this over rides PD002[1] setting I assume)

3. PD003,PD004,PD005 ... this is motor specific settings I'm not covering here.

4. PD011 set to 0. Now this is the interesting one. This is going to supersceed PD003 that you would think is the defined speed for Speed1.
But there is an assumption that as long as [FOR]ward is enabled (which it is, because its permanently tied low, isn't it?)the motor is turning and doing something and so would burn out if the setting is too low. But in GCode the spindle is turned on by its speed setting ie: S18000 or what it's a cheat we programme into the VFD firmware to turn the spindle off with a zero speed setting.
(granted there is an Mcode for spindle on but with NC studio you just have 4 speed options on 3 pins. 000 being off, 100 being low, 010 being...etc.)

PD044 is set to 02. Sets FOR connector to enable forward rotation when taken low.
PD047 is set to 22.  Sets SPH connector to enable setting in PD0088 when taken high.
PD048 is set to 24. Sets SPM connector to enable setting in PD0087 when taken high
PD049 is set to 23. Sets SPL connector to enable setting in PD0086 when taken high

PD080 set to 2.
That's the magic setting.

This allows signal from NS Studio to select the three(4) settings for speeds you will define below...
We've already looked at the PD003/PD011 issue so that is Speed1 ie: 0Hz
PD0086 is set to 133 for 8000rpm
PD0087 is set to 300 for 18000 rpm
PD088 is set to 400 for 24000rpm
I may change these settings depending how they work in practice.

If I'm wrong with what I've done here please let me know. If this has been a help please comment. If I made some typos please let me know.

Saturday, May 23, 2015

ER11 drag engraver

This post is a little off topic so I'm sorry about that. It will be relevant to somebody I suppose.
spring loaded ER11 diamond drag engraver
Above is a spring loaded diamond drag engraver. It's 3mm with a 120 degree angle tip. The issue with it is it needs to be spring loaded to allow for uneven surfaces, but there is very little space to build a mechanism inside an ER11 size collet. The commercial ones work externally to the collet. My thinking was if it is in the collet it would be more ridged and more accurate.
CNC spring loaded diamond engraver
Drag engraver apart
So here it is taken apart. An ER11 collet with a 7mm diameter.
A hard brass pipe(Albion Alloys, metric K +S!)
Polished 6mm steel shaft from an inkjet printer with a spring, I'm not sure where that came from!
I chopped the steel shaft with a hacksaw and stuck it in the lathe. I wrapped the shaft in masking tape to protect it from the jaws of the lathe, then drilled the centre to receive the diamond tip bit and trimmed the other end to take the spring. The spring is squeezed on. This is important for a couple of reasons. It ends up >6mm diameter therefor holding the shaft into the brass tube and so the collet.
That's morealess it. The extra lug at the end is just because I cut the main body of the shaft too short. The grey crap is PTFE/graphite dry lube.
To use...(engineers close your ears), I put it onto the spindle as usual then tighten the nut until the collet pinches the brass tube enough to stop the shaft moving, then loosen the nut a smidge. It should return when pushed in. So I'm using the collet slightly loose...

Thursday, April 2, 2015

The State of Matter as it stands.

DIY metalize
For SEO your supposed to add a caption! DIY Metalization.

A very quick update...this is the state of the system now. The steel belljar is working well. Sight glasses seems to be sealed ok too. After buying a very nicely priced butterfly valve.( Thanks to JF and his wife for the delivery!) I can now cut off the diffstack from the belljar. I got down to below the range of the pirani gauge. Oh yes, I'm sorry I really coped out. I bought a diff pump on Ebay...Interestingly the urge to get the DIY one is still strong in my mind. I do intend to revisit it in the near future. If only to get some closure!
Steel Belljar
Belljar Hoist Mount
 The jar is heavy so I will put it on a pulley and hoist eventually.

Metal Belljar Interior Metalize
Vacuum Chamber Interior
And the interior..stainless steel M10 threaded bars tapped into the base plate.(gas escape grooves cut accross the threads that are in the tapped holes. To try and minimize virtual leaks.). A rolled aluminium ring 5x25mm. Soldered at the join (my first aluminium soldering. Very possible. Probably not a good idea for sealing... Must fly!

Friday, June 6, 2014

A big jar of nothing.

 There it is with the view ports welded in. I went for one to view filament and on to view object being coated. (I didn't do the welding, I thought, as it was critical I leave it to the expert!)

 There was some distortion when the welding happened so I had to sand the flanges flat again. I made that little sanding thing to help. It took a while but I got then flat enough for the o-rings to take up any of the remaining irregularity.

 The strangest thing was the bottom of the jar was no longer flat after the welding process. It shrank upwards towards the welded pipe. I was very surprised. It was across a section of at least 50mm. I spotted it when I did a test pump down and the bottom gasket was buzzing as air rushed in through the gap! Back to the counter top with sand paper as described before.

 Above is a view of the o-ring seal on view port. The o-ring are viton(€16 each woops). 6mm cross section. The glass is a square in 12mm, normal type. I just got a glazier to cut it for me.
So the tube sits proud of the flange by about 3mm. This keeps the o-ring in place. I cut the clamping rings from 3mm aluminium. Drilled the top one tapped the underside one. It is split as you can see from the side view.
Oh and I pumped it down today, its tight! Yipee!