Comments for Prutchi.com

Comment on CO2 Laser Engraver/Cutter Addition to a CNC-Retrofitted Sieg X2 Mini Mill by David Prutchi

David Prutchi — Thu, 28 Mar 2013 19:07:06 +0000

With plexy, cutting is not done on a single pass. It takes multiple slow passes to cut through all the way, but it does so very neatly. Color of the plexy doesn’t make any difference to cutting rates that I can tell.

Regarding the Chinese machines, I have a 40 W unit in my office from Full Spectrum Laser. I like it very much, especially its Retina Engrave software that allows CorelDraw to treat the laser engraver as a printer. It cuts acrylic just as my diy machine. By chance I have a reference 3/8″ piece in front of me that I cut with 15 passes at 50% FR and 20 mA to the tube on the FSL machine.

Cheers,

David

Comment on CO2 Laser Engraver/Cutter Addition to a CNC-Retrofitted Sieg X2 Mini Mill by Polytech

Polytech — Thu, 28 Mar 2013 17:41:54 +0000

Thanks, David! Wow, 1/4″ plexi (acrylic) with 18W of IR! (what wavelength is that, BTW?) Epilog does not even call their 30W laser a cutter/engraver – it’s very much only engraver by their own admission. I think the only machine that earns the “cutter” designation by them is their 60W. Is there something particular about the output of this tube that makes it more capable perhaps? You’ve got me very intrigued here.

I was looking at the Chinese machines that come with 60 and 90W tubes but they are very bulky, so I’m mulling over the idea of building my own. I’m fine on the CNC and motion control part but the actual inner workings of the laser beam source is still a mystery to me, so I will appreciate any comment you may have on the cutting ability of your particular implementation since it does look more compact and rather easier to make than those with larger tubes.

Does the color of the plexi play any part, by the way? Do you happen to remember the feed rates you’ve used?

Thanks!

Comment on CO2 Laser Engraver/Cutter Addition to a CNC-Retrofitted Sieg X2 Mini Mill by David Prutchi

David Prutchi — Thu, 28 Mar 2013 16:51:14 +0000

Hi Nick,
Thank you for your kind comments. Regarding your questions:
I regularly cut balsa and up to 1/4″ plexy
The beam is focused using a 1″ FL ZnS lens
Transparent plexy is sufficient to filter the relatively long-wavelength IR beam from a CO2 laser

Comment on CO2 Laser Engraver/Cutter Addition to a CNC-Retrofitted Sieg X2 Mini Mill by Polytech

Polytech — Thu, 28 Mar 2013 15:45:55 +0000

Awesome build! Pretty much the first laser cutter/engraver I’ve ever seen without flying optics. I guess, it must be the smaller size of the RF-excited tube that makes it possible. So, what type of material / thickness can be actually cut (as opposed to engrave) using 18W of power? Can you cut balsa sheets? Also, I’m very interested in whether you had to focus the beam and if yes, then how, can you share?
Sorry, so many questions in my mind … so, is a sheet of transparent plexi enough of a filter for the IR beam (scattered as in may be in the reflections)? Thanks!

Comment on Abigail’s Whimsical Sand Pendulum by Kristy of Portland

Kristy of Portland — Mon, 21 Jan 2013 08:48:19 +0000

Thank you for posting! Very informative directions and photos. Cleaning out our garage, I found 2 antique carpenter’s “plumb bobs” and remembered those cool “Pit and Pendulum” sand pendulum gifts and thought, “I wonder if I could just make it myself for guests to play with OUTSIDE?”

I also thought, surely someone has figured out how to make this at home. Thank you again for posting this information! I can’t wait to get started.

Comment on d.i.y. CO2 Laser Power Meter by Chris Eccleston

Chris Eccleston — Sun, 20 Jan 2013 22:17:57 +0000

Hey nice work!

Im really interested in making this device to test the power output and calibrate a second hand c02 laser I have acquired. Apparently its a Epilog Legend 32EX 120w thats only kicking out 25w

I have found a K type thermocouple and meter with digital display for £5 on ebay… am I right in thinking all I need to do is drill a hole aprox. 1mm in diameter in the side of some 3.2mm anodised aluminium and attach that to a CPU heatsink out of an old computer (I have a graveyard full!) and power up an old fan along side?
Can you give me a more detailed description of the graph, i’m pants at maths but fortunately for me my best mates mum is my old high school math teacher!

Your help would be greatly appreciated. I also have a few other queries for a knowledgeable person like yourself, that I cant seam to answer myself using the internet etc.. to my satisfaction.

I use nichrome wire to create a hot wire at work, using a 140w variant for stick-welding. Its an age old hack that no one ive ever been showed by understands.

Now all it comprises of is a wire 2000mm long in a 18mm wide, 18mm deep channel on an MDF bench with a spring one end and its fixed to a nail the other.
We use a block of sandstone with a hacksaw grove to hold the wire straight
its powered direct from an arc welding transformer using a copper connector.

What I want to know is how do I control the heat, or amperage to shorten the wire, or decrease the heat of the wire, and also would it be possible to use something much easier to find than an arc welder.
IT would be a very useful hack, It would be great if it had a simple variable heat dimmer and timer on off.

Thanks for reading. Im a graphic designer by nature so if theres any way I can help you out back, in that field let me know!

Kind regards

Chris Eccleston

Comment on Pilgrimage to the Holy Dish by anon

anon — Sat, 19 Jan 2013 06:00:32 +0000

Sir,
very nice. I have corresponded with you re med electronics and/or rad measurement physics. I too have visited the Holy
Site (so humid! I had to take my shirt off despite being heavy and modest..) and its very neat. Am glad to see you continuing the efforts with enthusiasm.

Keep calm, carry on, and enjoy.

Comment on Back from the Galapagos Islands – My best trip yet! by diy Physics Blog - Bad Physics at the Equator – Shame on the Intiñan Solar Museum!

Sat, 08 Dec 2012 19:05:06 +0000

[...] Abigail and I just returned from a trip to the Galapagos Islands. On the way, we visited the iconic Mitad del Mundo (Middle of the World) monument which commemorates the 18th-century French Geodesic Mission expedition carried out for the purpose of measuring the roundness of the Earth and measuring the length of a degree of latitude at the Equator. [...]

Comment on Maggi “Cook Studio” in Leipzig: Delicious Home-Cooked Meals from Ready-Made Packages – A Culinary Oxymoron? by Bipin Barla

Bipin Barla — Sun, 28 Oct 2012 10:30:12 +0000

I am intrested to know more about your maggi cook studio.I would like to say that in India people are very found of maggi but we do not have a cook studio like the one shown above.waiting to hear from your end.

Comment on d.i.y. Handheld Multichannel Analyzer (MCA) based on 16F877 PIC Microcontroller and LCD by David Prutchi

David Prutchi — Mon, 01 Oct 2012 12:11:15 +0000

Hi Peter,

The schematic for the LABX1 is at: http://melabs.com/downloads/labx1sch.pdf

The most up-to-date schematic for the S/H and logic is mentioned in the post at: http://www.diyphysics.com/wp-content/uploads/2012/02/mca-schematic.pdf

Before developing a hardware-based MCA, please consider the following option: http://www.diyphysics.com/2012/09/21/using-the-79-sainsmart-dso201-pocket-oscilloscope-and-gammagrapher-with-the-pmtscintillation-probe/

Cheers,

David