Messages

261

General Mach Discussion / Re: Physical buttons for plasma

« on: March 10, 2016, 09:18:16 AM »

The steep sides are good... It's called the angle of repose, although the metal is molten.

I've tried to find the angle of repose for iron filings, but can't find the link now or source, but 60 degrees seems to be a number from somewhere.

Also think about what you intend to cut... Stuff with coatings can give off toxic fumes (galv etc)... Hence better to use new plate than second hand... Which I know you are not but someone following this might)

262

General Mach Discussion / Re: Physical buttons for plasma

« on: March 10, 2016, 04:13:51 AM »

How big is your table Dave?

Sorry Hood, can't remember (and 29 pages is a bit so search through...), how big is your table?

263

General Mach Discussion / Re: Physical buttons for plasma

« on: March 10, 2016, 03:36:30 AM »

Dave & Hood, funny thing doing posts after midnight.... gives you time to think a little (note to self, do before opening keyboard... [or mouth])

Dave, 3200m³/hr = 889 l/sec, & yup that is an axial fan.

Problem with axial fans is they have very little pressure displacement across the fan as said above, and manufacturers like to quote airflow numbers with the fan tested without any ductwork on it / or induced pressure loss (free air displacement).... hence when looking at a fan curve such as the one below, you can see that some manufacturers will choose the point of most airflow at zero pascals of pressure displacement at the far right of the curves (in day job be very suspicious of any fan manufacturer not publishing a fan curve for a fan but just quoting one number without a corresponding pressure displacement).

http://www.cibsejournal.com/wp-content/themes/cibsejournal/images/2011-12/images/figure-1.png

If you are adding ductwork on to it (flexible / ridgid) you need to consider the pressure loss (even roughly), and also the termination (louve, or even free air discharge), and also the intake.

(I'll try to do this over a few posts, if anyone is interested)

264

General Mach Discussion / Re: Physical buttons for plasma

« on: March 09, 2016, 07:32:45 PM »

Hi hood, I think Dave has got an extra zero in the 3000cfm (~1.2m3/sec) number above from a 12" axial fan.

From the day job, you could try to improve the capture airflow by using a set of vent grilles or slats below the cutting bed that are 60degree upside down. V shaped slats with maybe 1.2mm copper cladding over the top so the plasma kerf metal spray does not stick to them

You could also place a piece of plate over any unused parts of the table and this will increase the airflow over the used bit of the table.

The rough rule of thumb would be 0.5 to 1m/s per square metre of table...but you need to consider how much of your table is covered in plate normally...   You also need to add a bit for leakae plus fan performance.

Look for mixed flow fans... Stuff like vent axia powerflow fans will get you better performance than an axial fan (airflow at pressure)... Axial have very little pressure (head) capability.

Rob

265

General Mach Discussion / Re: Physical buttons for plasma

« on: March 05, 2016, 12:28:18 PM »

2p suggestion.... have you thought about offseting your two Y axis so that you get more travel use of your table?   As its drawn, offset toward the back of the machine, given as its shown your torch will be on the front, hence can reach the front rail of your table at the front but may be 100mm from the back of the table?

Is the rear of the table not going to catch on the frame (around where the rails are) when you tip it up, so you may need to offset the table pivot point further forward?

(arm chair smart a$$£""£ I know, sorry).

That way if you offset the Y rails back, they can act as the horizontal stop (but it would tip up the other way.

Also you need to think about how you will lock the table whilst you are loading plate or it may tip up.

The central rail may also become consumable (the central slat support rail, as the cutting power of your torch may exceed the offset depth of where the rail starts).... maybe using angle iron will improve your build time for the slats (but the cost would go up)   I'll post a picture of my slats later may help someone out for an idea in the future.

10 engineers, 10 alternative solutions

266

SmoothStepper USB / Re: Need a little help troubleshooting an ESS Mach3 installation

« on: February 19, 2016, 04:00:48 AM »

I'd suggest reposting on the Warp9 forum and Andy will walk you through the setup (if required) the 255.255.255 is a bug and to be ignored.
http://www.warp9td.com/index.php/kunena/index


The suggested route is to use the SCU tool for the setup and get the pings etc.
http://www.warp9td.com/index.php/gettingstarted/setting-up-my-pc

267

General Mach Discussion / Re: SPINDLE FREQUENCY?

« on: February 18, 2016, 09:57:11 AM »

You can add some debounce to your settings... That will aide in removing or masking some of the noise

Check your cable routing.

You can add some 0.1uF ceramic capacitors (100nF)

Rob

268

General Mach Discussion / Re: Reference Home Error

« on: February 16, 2016, 03:09:19 PM »

If you go into the C:\mach3\ folder,  .... Select show folder contents details, sort by filetype, down the bottom of the list should be the XML.files.... One of which should correspond to your profile name.

269

General Mach Discussion / Re: THC moves on the Z axis...

« on: February 14, 2016, 08:08:10 AM »

Well, that has confused me if g00 passes and g01 fails.

Interesting you got the acceleration higher up to 5000mm/s/s

270

General Mach Discussion / Re: THC moves on the Z axis...

« on: February 13, 2016, 02:55:00 PM »

Well it works for you at 3000mm/min... And you are happy with that?.... Start with that (I.e just change the ustep dip switch, plus z axis steps per mm from 500 to 200 and see how it runs... Then increase your acceleration (and see what you get shunting the z using the keyboard THCUp and THCDn buttons you've setup.

If 1500mm/min is what you had before changing the leadscrew and you know what divot you ended up with that... Then that is your ultimate cannot go worse than that point.

Terry had an interesting point about the THCOK before motion.... Especially on thin stuff and high amps as some of the hyperthem cut tables have zero or near zero for pierce delay....hence not sure if you can decend to cut height on the move (never tried it.... Still waiting for my new machine to arrive)