Newbe here, 3 machine homing where should it go and placment

[james383]

Newbe here, Got my machine up and going even made a few name boards but having problem with knowing project placement and where the M3 should home to.
Mine homes right rear , have end stops set for 10in print or cut. I place my project left front after ive homed the unit , I run my cutter to left front and zero off there on all axes
then load print and send and it never seems to really cut center of the board even if i tell it in my design program size of work space and project size.
I will place my project say in Makercam right square to the corners and design what i want then save and export Gcode and load under UGC and send it and seems it never
really places on the work board right.

Machine homes top right (Is that right?)
I place my build lower left and zero off from that corner (is that right?)

Remember im new to this and im used to my 3d printers but totally differ i can point and tell my prints where to start on the bed or it just centers the print automatically according to bed setup and size.

Im trying to learn this but every machine or video i see they set there machine up differ or using differ software. Im not ready to go out drop $1000 bucks on software yet till im sure I know this
and then I might still stay with whats free at first and save up for a large machine bigger build, but till then im just trying to enjoy this and learn without having to read 100hrs of books and same on videos . Ive followed what i have seen up till now but fact is not many videos online showing M3 running other than load cut done and none showing the basics I guess.

Any help would be nice. The room has been friendly on getting me going after a bad UNO board and driver board, Power cord bad but then thats the fun part is learning from scratch.

Thanks...

[aforww]

Read the CNC beginner sticky.

Homing should go back rear right. It's purpose is to have a constant known position. Machine zero.

Now, work zero or WCS is where you tell it to start cutting. If in your design, your origin is in the center, then you must zero the machine axis to the Center of your material. The WCS zero is wherever you want but the origin must be the same from design to machine.

[james383]

So after placement of my work peace or cutting material i would then zero the bit in the center of that and then tell it to SEND and let it start cutting. I was placing my work peace front left the zeroing it left front as well so that's wrong? Secure peace im working on on the bed after Homing then zero bit in center of my work peace and then SEND ?

[Derek the Admin]

As Aforww mentioned the beginner's guide in the general forum (it's a sticky at the top) will help you get your head around these concepts.

Unlike 3d printers, in CNC routers/mills, there are multiple coordinate systems. There are machine coordinates which describe where the cutter is in relationship to its homing switches. Basically, where it is in the cutting space. Then you have work coordinate systems which are basically used relative to the piece you are working on or a fixed location clamping fixture. With homing switches, you can take advantage of work offsets (offsets because the machine thinks of them as offsets from machine origin) in the G54 through G59 coordinate systems. The beginner's guide will explain how to set these up.
The quickest way to set a quick work origin though is to use the G92 command. As Aforww mentioned, you have to note where your origin was specified in your CAM software when you generated the g code. Let's say you were wanting to cut a 6 inch by 6 inch circle. You program it in your CAM software and set the center of the circle as the origin. Now let's say you have an 8x8 piece of wood that you want to cut this circle out of. You could clamp the piece down, jog the cutter to the center of the wood, then set the cutter on just on top of the wood (because you should set the top of the part as the Z origin in CAM). Then type G92 X0 Y0 Z0. This would tell the machine to zero the work coordinates to the spot its at right now. Now everything run in your g code file will run with that 0 point.

[james383]

Thanks i will try this again, home machine then mount my peace of wood im going to cut on the Spoil Board and then jog the bit to the center of the work board zero the Z there they type G92 X0 Y0 Z0 and run it. I was using the UGC program and just after joging the bit to left front peace of wood id use the UGC and click on the X,Y,Z, zero tabs then SEND G-code . KInda the same but i was not jogging the bit to cent of work and setting my Z off there.

[james383]

No luck placed board center of machine then homed machine then run bit to center of wood and run z there and set clearance and then the G92 x0 y0 z0 and run g code it went off the board so i aborted it did like I had before pulled board lower left jogged the bit over to lower left Z-ed it off clearance and then hit zero x y and z from the UGC software loaded G-code and run it , it went ok but still not centered on work board so im loosing something in the reading or understanding how to align up your work to cut .

[Derek the Admin]

Can you post your G Code file please? That will help us understand how best to help you. You can add it as an attachment after clicking "reply."

The machine won't have a way of knowing the dimensions of the board you are carving.... it will only follow the travel dimensions of the file you are using.

Let's just say for example you wanted to engrave the letter J in the center of a piece of plywood that was 8"x8". There are a few ways to achieve this, but here are two methods:
Design it so that the J is in the center of an 8x8 square. Set the origin as the bottom left of the square. Put the piece of plywood on the machine table and clamp it down, squaring it up. Jog the cutter so that the center of the cutter is at the bottom left corner of the work piece, right at the top surface. Type G92 x0 y0 z0. Run your file and if all is done right the J will be in the center.

Alternatively, you could design the file so that the J is in the center and set the center of the square as the origin. Put the piece of plywood on the table just as before. With this method, you have to find the center of the plywood. Probably the easier way to have done this was to use a ruler or tape measurer and put a little dot in the center with a pencil or pin. There are other ways to do this, but this is the easiest. Jog the machine over to that dot you made. Type G92 x0 y0 z0.

As you get more advanced, you'll be able to use clamping jigs or "locating jigs" and, sense you have homing switches, you'll be able to set up work coordinate systems that can be accessed even after reboots that are centered on certain locations in the machine. Try the G92 methods we described above though and we will help you work up to that.

[james383]

I tried both ways i think Ive always homed the machine first , mounted my peace of wood say 10x10" fixed it to lower left then i moved the bit to lower left and down off the left corner of the wood and in the UGC software I hit zero x zero y zero z and then loaded the Gcode and pressed SEND and it starts cutting but its always off an 1nch or so. I tried the other way mounted the peace of wood lower left moved the bit lower left clearanced it off the wood then hit G92 X0 Y0 Z0 and loaded Gcode and pressed SEND and it went off the backside and started cutting and hitting endstops and belts skipping so I stopped it. Now each time i have homed the machine before anything. But here is the Gcode i worked up in Makercam and it was placed squared or where ever it moves it to and i worked and saved the Gcode from there.BEAR-PLAC.NC (1006.98 KB)

[Derek the Admin]

I'm wondering if you used this as just an example... or if it is part of the issue. If your wood piece is 10 by 10 and you go by the bottom left corner than that particular file will be a bout an inch off from center as the file itself looks to be making a piece that is about 7.5 x 7.5.

[james383]

I made the file under Makercam then saved it and loaded it under UGC and centered the 10x10 peace of wood i was cutting out in the lower left cornet and Zero it all out at left lower corner.  But even the cutting is all crazy as I tell it to cut a pocket 1/8 in every program is in Inches not MM so im good there. But it wants to cut 1/4 deep , if i tell it do a step down depth of say 1/6th inch or -0.0625 it wont take that out first cut it wants to try maybe 1/8th or more and do like 4 cuts and like 2hrs for the whole job of basic letters.  This is my setup under MAKERCAM

Tool Dia 0.125 1/8th in
Target Depth 0.125
Saftey Height 0.125
Stock Surface 0
Step Over 40
Step down -0.0625 1/16th in
Rough clearance 0
Feed Rate 30
Plunge Rate 10
Direction Counter

Like I said i only want to cut out the letter 1/8th of an inch deep nothing more just cut out letters for 1st time cutting
and it want's to cut on first pass maybe 1/8th in maybe more and then 3 -4 more passes to cut down a 1/4in in depth.
2hr printing time it says Under UGC program. I let it run a few times near an hr and it was already down past my 1/8in cut i wanted so im loosing
something or miss understanding what Makercad wants for inputs.

It still cuts to the right maybe 1/2 3/4in to much. I have checked end stops set all that so the bed or cutting space is only 10inches 10x10 and
Zero it lower left and zero all x,y,z, then load file press send and it does all the above but to the right like i said 1/2 3/4 inch and wants to cut double
what i want it to and im not sure about time wise but 2 words on a 10x10 peace of wood near 2hr seems long maybe not im not used to cnc.

So my main question and problem is why is it wanting to cut co deep and maybe slow and why over 3/4 inch to the right even tho i zeroed
the machine lower left right on the tip and even under Makercam told it to load cut 0 to 0 lower left .  Im kinda lost right now and have tried 15 cuts
and not had any luck with a full finish cause i stop it when i see it cutting even the first cut down past what i set the full cut to be.

Any help would be nice. I will send a screen shot of my Makercam setup.Attachment Deleted

[aforww]

I don't use makercam so I couldn't tell ya what's going on. Have you tried another program like easel or Fusion? That will at least tell you if the problem is a machine setting or a design problem. Narrows things down a bit.

[Derek the Admin]

Can you upload the G code for the exact file that you are talking about now? I see it's a different design than what we talked about previously.

Also, open unviersal G code sender and copy and paste or take a screen shot of your settings by typing $$ and pressing enter. Have you used Easel to try to connect to your machine by chance? If so, it almost certainly has reflashed your settings, which would put your steps/mm off, acceleration, velocity, etc different from our defaults.

What you are trying to do should not take 2 hours. One tip is that your feed rate is too low. 30 IPM is a bit too slow. Let's start by cranking it up to about 50 IPM. Your stepover is set to 40 percent of end mill diameter. That helps produce a good bottom finish but it means that its only going to stepover 40% of 1/8 inch, or 1/20 of an inch at a time.

Next, while you are getting a feel for things and trying to dial stuff in why don't you try a profile operation instead of a pocket operation. Because a pocket operation requires clearing out all the material inside the boundary of a shape, it just takes longer. Try to select a profile operation for now while we get a feel for things.

For now though, lets get your g code for the file you just took a screen shot of and your $$ settings please. From there we will be able to diagnose things.

[james383]

Derek , thanks again for the help. The code for the machine looks to be ok but will send a snapshot of it. Will bump up the rates see how that works as well. You talk of Profile and not a Pocket I wanted to just cut the letters down into the wood so thought that was a pocket and easiser to do . I'm still at a loss why it's wanting to take off more than I ask it to . It would be a disaster if this was metal as it was trying to cut over 1/4 when I tell it not to go over 1/8 total cut . Ill post the info you ask for and the lettering sign I was working on the other day. I have tried even more letters to see how it would work so will send that file I tried 6 times yesterday to cut and each time the first cut was deeper than the whole cut should have been. I think I'm doing the math right I have all programs set to INCHES as MM screw me up . I told it I wanted depth to be only 1/8th .125 ill let you look it over see where I'm screwing up. 
   LARRY-CAVE.NC (732.85 KB)

[Derek the Admin]

You are correct that a pocket is what cuts down into the wood. If that's what you want you are choosing the right operation, I was just pointing out the difference in the two operations time wise.

Okay, let's do this. I want to test motion completely independent of any kind of cutting file.
Jog the machine so that the cutter is at the bottom left and just on top of a piece of wood. Give these commands:
G92 X0 Y0 Z0
G20
G0 z0.5
Stop and measure. Is the bottom tip of the cutter now 0.5" above the wood? If not how far exactly?
Now give this command:
G0 X5
Did it move 5 inches to the Right?
Now give the command G0 Y.
Did it move 5 inches?

Regards

[james383]

I tried the new settings and did both the profile and pocket cut and each took around 30 minutes but still seems to want to cut down first pass more than what I ask it to. I think I'm asking it to cut 1/8th in deep total depth and only cut 1/16th or 1/32 at a time but maybe I don't understand Makercam and what its asking for input numbers. The cut is lots faster but harsh but then this is wood and going to be noisy jejejeje it cuts clean just I'm scared I'm not understanding the input numbers and all what they should do . The total depth its cutting on the level corner or where I Zero from left front corner is .0855in left rear is .1030in like I said left rear is high but not a bother right now just this cutting depth thing and I'm sure it's me not knowing the input right , I got the numbers right just not sure if there going into Makercam right places. But thanks it is cutting faster with going up from 30 to 50 on the feed rate and overlap from 40 to 50 .