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bdurbrow / grbl-Mega

An open source, embedded, high performance g-code-parser and CNC milling controller written in optimized C that will run on an Arduino Mega2560
https://github.com/gnea/grbl/wiki
MIT License
35 stars 8 forks source link

New Machine Setup Questions #20

Open bdurbrow opened 4 years ago

bdurbrow commented 4 years ago

From a comment by @Elpablito:

Hi bdurbrow At first congratulation for the fantastic job you have done, I am following you on github since last year when I start to think to make CNC.

Stop that! You are going to over-inflate my ego! :smirk:

Sorry for my English I shall try to make my best. I made a machine, bat it is my first one, so I am not an expert in working with such a kind of machine. The CNC is made with some plastic parts good for wood or soft materials. Actually, I have used an Arduino Uno with its shield for stepper drivers and it seems it is working properly, at least for the tests I have done. For sure, since the beginning the idea was to have a standalone CNC so I am trying to replace Uno with a Mega that I was having somewhere. Unhappily, I faced these kind of problems that I am not able to solve.

  1. I have modified the hardware setting $0……$132 with UGS and when saved. If I disconnect the board and then reconnect the setting are the old ones not the new ones. It seems that save action do not write EEprom.

I'm going to assume that you are using the October 2019 update version. In the main readme.md file that shows up on the main page of the github repository; where it talks about what's new in the October update; on the fourth item down; it covers this. Basically, send a $255=1 command via the serial port to save your settings; or use the settings editor found in the System menu. The reason this was changed was to accommodate a user who was going to be switching back and forth between regular and laser modes. With this you can switch any setting - including $32, laser mode - and have it not do a write cycle on the EEPROM (and thus wearing it out prematurely) unless you actually want to save the current settings.

  1. Why in the home cycle homing Z is optional and why is the third action, moving before Y and X and then Z? If any reason I shall prefer to move Z as first action.

I haven't yet done anything significant with the homing cycles; it's more-or-less as I found it in the official Grbl-mega version. It's something that does need addressing; and I think will get to it as part of the next update.

You're right though... that is strange that it's setup that way.

  1. Which is the use of RAPID_OVERDRIVE potentiometer?
  2. The FEED_OVERDRIVE Potentiometer is to decrease the set speed of FEED?

The override potentiometers allow you to make adjustments to the feed rate, spindle RPM, and rapid speed (how fast the machine moves when you give it a G0 command). These adjustments take effect immediately, while you are running a program (so if the machine starts chattering or squealing you can make adjustments to get rid of the problem). They are optional equipment, but I do recommend having them. You enable that feature in the config.h file, down towards the bottom of it.

If you don't have them setup, you can still adjust the overrides via the serial port.

  1. Is the SAFETY_DOOR the door of the cabinet you need to close before run or it is an escape way? In such a case what is it doing? Thanks

Basically, yes - it's the switch that's on the door of CNC machines that are in an enclosure, and it stops GRBL from moving the machine while the door is open. Or at least it's supposed to -- depending on a variety of factors, it can still fail, so people should always be careful and not put themselves in a position where the machine can hurt them.

Saur0o0n commented 4 years ago

For DRV8825 2,5A is probably too much (unless you have some specific version) - recommended current is 1,5A or 2,2A with heatsink AND forced air cooling. So I wouldn't go above 2A with it. Yes, you will loose torque - and everything depending on it like speed, acceleration etc.

Elpablito commented 4 years ago

Hi Saur0o0n Ok you are confirmed my doubts. Now the question is: there is an already tested solution to drive a 3Amp stepper using mega and ramps? If you give me a suggestion I will look for.

Elpablito commented 4 years ago

Hi Saur0o0n TB6560 may be a possible solution

Saur0o0n commented 4 years ago

Hi,

So far I had 3 drivers (all Chinese production). Two (max 48V/5A) I've burned without any particular reason - they stopped working properly (there where buzz), after a while one burned totally - those where based on TB6600. Chip inside seems to be real. I had also "faked" TB6600 - this are based on smaller chip that cannot dissipate enough heat - that's why it's no go for 2A+. This one was working, but for small currents. Now I have DM556 (this are based on ARM micro controller) - I can recommend them. They work nice, motors are running quite silently and on hold they can lower current (so less heat on motor). One problem was that they are rated to 50V but they had 35V capacitor on main voltage - it blow to my face ;) almost immediately after connecting (my voltage is 48V) - but after replacing caps, they are fine. I bough them here.

bdurbrow commented 4 years ago

@tevins - Sorry about the delay; things got busy here and I haven't had much free time. As mentioned above:

Select the .nc file, and then press the "Enter" key or push the Encoder Knob in. The file should then start running.

Other behavior (i.e, activating with the Cycle Start button) will be added in the next update.

Elpablito commented 4 years ago

hi bdurbrow I am back after long time becaure I had to remake the CNC and because all the problems of this year. I hope you are OK. I am not able to discover how P+, P-, and Part are working. Could you give a suggestion or say where I have to looK for ?

Elpablito commented 4 years ago

Hi I hope that covid19 is not the reason because no one has been on this forum since 5Mar. There is some one who is able to explain to me how P+, P-, and Part are working ?

austrian1 commented 3 years ago

Great job bdurbrow . the button reset although makes you go to menu and reset the alarm. and one more when you run a program from sd card you see x,y, z changing, if you go to main menu afterwards i didn't find a way to go back to x,y,z without cancelling the program . maybe you could add an external button for coolant.