Sturdy and Fast all Steel CNC , my first build

[m_c]

The frame looks good.

The welds look fine considering you've not ground the mill scale of before hand. Although MIG welding will burn through the scale, it can lead to weld contamination as standard MIG welding can only burn of a limited amount of contamination.

[Boyan Silyavski]

The frame looks good.

The welds look fine considering you've not ground the mill scale of before hand. Although MIG welding will burn through the scale, it can lead to weld contamination as standard MIG welding can only burn of a limited amount of contamination.

Thanks for the heads up. next time will not only grind 1mm the corners but as you say.

Here are 2 recent pictures. Just soldered the hardstops for the gantry from 100 UPN profile. My friend insisted on soldering 4 short legs, again from UPN100 profile. Strengthwise i would have soldered 6 legs instead of 4, or none at all and lay the machine and thin layer cement the machine on place but i was very curious of the deflection of my design.

Now just measured it so here is the result:

1. Applying 100kg static force/me/ on any one of the bead beams leads to 0.045 mm deflection in the middle
2. Applying the same 100kg to middle of the raised sides supported only at both sides by 9 cm legs from 100UPN profile leads to 0.03mm deflection on that side.

Conclusion: With gantry and bead mounted in real working conditions the overall vertical deflection of the machine will be unmeasurable or less than 0.01mm which is irrelevant especially with 0.8kw spindle. So first impressions are perfect.

Anyways, i will most possibly insert pads in the middle of the machine when placing it on its place, so it will stay rigid and quiet

PS. In fact using the excel file for calculating deflection on gantry and gantry side, i guess the real final value of deflection in all directions of this particular design of the finished machine will be 0.0035mm. Which i believe is great.

[kingcreaky]

it looks really warm there... ive just returned from holiday in turkey, to miserable cold england. :(

top work... keep the photos coming...

[Jonathan]

Conclusion: With gantry and bead mounted in real working conditions the overall vertical deflection of the machine will be unmeasurable or less than 0.01mm which is irrelevant especially with 0.8kw spindle. So first impressions are perfect.

Your test shows that the deflection due to the frame will be very small (<0.01mm), but remember the linear guides and Z-axis especially will all lower the stiffness, so overall your deflection will be greater. Still, your gantry design looks reasonably strong so I expect it will be fine.

[Boyan Silyavski]

Your test shows that the deflection due to the frame will be very small (<0.01mm), but remember the linear guides and Z-axis especially will all lower the stiffness, so overall your deflection will be greater. Still, your gantry design looks reasonably strong so I expect it will be fine.

Thanks. I am aware of that. For me this build is a preliminary build to my real machine. A kind of experiment. Something like how far i could go at every step.

As the machine we all know is a sum of its components.I constantly meditate on "the machine is strong as its weakest part". The Hiwin blocks are with A preload, the deflection calculator tells me the gantry sides deflection cutting aluminum will be lower than 0.01mm, so i guess the weakest part will be the Chinese spindle bearings and the bit. I will be extremely happy if i succeed in making a precise machine, just for the sake of it.

[Boyan Silyavski]

I need some help here with the Leadshine AM882 drivers and the SY60STH86-3008BF motors from Zappautomation.

-As far as i understand the auto finding of the parameters using the dip switch would be enough?

-However i wonder what step/micro-stepping should i use with the 1605/z/ and the 1610/x,y/ ballscrews? having in mind the way i build the machine.

-Also about the Switch 8 at the drive.
the manual says:
Pulse signal: In single pulse (pulse/direction) mode, this input represents pulse
signal, each rising or falling edge active (DIP switch configurable); 4-5V when
PUL-HIGH, 0-0.5V when PUL-LOW

So i asume rising is Pul High and falling edge is Pul Low. I wonder which one will work with my C23 board from CNC4PC

[Jonathan]

The microstepping setting is generally first limited by the output frequency of your parallel port. Using higher microstepping can help with reducing resonance problems, although those drivers have more advanced ways to deal with that so it's hard to say. Generally people don't use finer than 1/8th microstepping as going further can reduce performance, but if you can even use that will depend on the maximum frequency your parallel port will output and the feedrate you require.

For example, suppose you want a feedrate of 8m/min (sensible for cutting wood) with the 10mm pitch screw driven via a 1:1 ratio with a parallel port that can only output up to 25kHz (a lot will do more, but not all):
Screw angular speed: 8000/10=800rpm
Base frequency: 800/60*200=2667Hz
25000/2667Hz=9.4 ... so nearest is 1/8th microstepping with the above conditions.

[EddyCurrent]

http://www.mycncuk.com/forums/machin...-mach-3-a.html

From what I've read 1/8 is a good starting point

RE. switch 8 I guess if it won't work one way then try the other

[JAZZCNC]

Bloody heel all that typing and Jonathan had already said it all . . Lol

RE. switch 8 I guess if it won't work one way then try the other

Not that simple Eddy it will work in either mode but if pulse is on wrong side then it will drop a step on direction changes.!

[JAZZCNC]

However i wonder what step/micro-stepping should i use with the 1605/z/ and the 1610/x,y/ ballscrews? having in mind the way i build the machine.

Well depends a lot on your PC and how good the parallel port is and what speeds your looking to achieve. PP and PC speed to some degree will determine the Kernal speed in Mach3 and how many pulses you can put out which in turn will determine the speed you'll get from the machine. Higher micro steps require more pulses to achieve same speed has lower MS but they give smoother running motors and to a lesser extent some resolution.
Personally I don't go higher than 10x or 2000ms and this is my preferred choice if PC can handle it. Higher MS also helps with resonance but these drives are great with handling resonance so it won't be a problem and if it is you can change tune it out using the software.

So i asume rising is Pul High and falling edge is Pul Low. I wonder which one will work with my C23 board from CNC4PC

I would agree but check with Arturo and I'm think it may even be possible to change a jumper on the board has well to suit but either way your covered because the drives allow it.
If you can't find out then you'll have to make some witness marks run some G-code and then check if it's lost position. If the pulse is on the wrong side it will drop a step on every direction change so won't take long to find.