Newbie- part setting issues.

[autobionics]

Hello All

I am very new to cnc'ing and I think I am having trouble with setting up the machine before starting to mill. I have a EX plus series one, and can power up and home the axes etc.
What would you guys do then? I centralise the axes with the jog button and then try and start programming. I have loaded a dxf programme from the A: drive and converted to .pgm, but when I try and load it i keep geeting error message saying axes limit, at a line in the programme that is cutting an arc. The part itself is no bigger than the palm of my hand so I dont know what is wrong.
Is there a sequence that you really need to follow on these machines from powering up?

I must add I have built up this machine from parts, so do you think the motors and encoders are not set correctly?

Is there any books websites that can assist us newbies?

Thanks in advance

Steve

[colin1544]

Hello again Steve sorry I have not been in touch but you have learn't how to home the machine to the travel limits what you have to do now is set the X axis & the Y axis datum postions, so move the bed somewhere midway in both the X & Y axis and press the key for SET XYZ the sub menu then comes up for X enter 0.0 Y 0.0 and Z0.0, you will then notice that the DRO readings all read 0.000. Now load your test program and it should run OK, if not give me a ring on 01159389014. Cheers Colin

[autobionics]

Originally Posted by colin1544 Hello again Steve sorry I have not been in touch but you have learn't how to home the machine to the travel limits what you have to do now is set the X axis & the Y axis datum postions, so move the bed somewhere midway in both the X & Y axis and press the key for SET XYZ the sub menu then comes up for X enter 0.0 Y 0.0 and Z0.0, you will then notice that the DRO readings all read 0.000. Now load your test program and it should run OK, if not give me a ring on 01159389014. Cheers Colin

Colin

Thank for your reply, I shall give it a go tonight and see how I get on. I will give you a call this week also and have a chat.

I had been moving the table to the mid position, but used the F4, F5 and F6 soft keys to set the zero position. I will use the method you say and see how I get on.

The dxf part i have is from AutoCAD and it is in millimeters, I am guessing the machine needs setting to mm before any programme are loaded? Also, does it matter if it is INC or ABS?

Cheers

Steve

[machintek]

Good God! You really need to know what you are doing before you get hurt. Machining involves knowing feeds and speeds and what tools to use for what material (application). Also work holding is vital before the piece becomes a unguided flying object and per Murphy's law will be going in your direction. There is a reason that a journeyman machinist has a certificate.
All CNC moves in absolute are tied to part program zero. Incremental moves are tied to the last position. Thus in incremental a X move of 5 inches called up twice will result in a move of 10 inches. X5.0 called up again in absolute would return the cutter to 5 inches from X zero. This is a very basic concept.
And yes. If your machine is in inch and you try doing metric stuff you will quickly run out of machine travel.
Sorry, just concerned for your well being.

George

[autobionics]

George

Thanks for your concern. I must stress that my posts do look like I am a complete novice, but rest assured I take myself and others safety of a high importance, and I do have alot of non cnc machining experience, so feed and speeds, cutting tools etc are known.

Everything I am doing is in fresh air at the moment, and until I am 100% sure I understand exactly what is happening and I also understand what my interactions are doing I will not be fitting cutting tools and making swarf.

We all have to start somewhere, and this is why I am asking the experts for advice.

Thanks for you advice and concerns, it is much appreciated.

Cheers

Steve

[derekBPcnc]

Hi Steve,

Make sure you know where the x0 y0 of the Autocad drawing is.

i.e. Load the drawing into autocad and move the cursor untill the xy cordinates show zreo. This is the datum point of the drawing and also wil be where you need to zero in the real world.

When I first started, my part was drawn in some obsqure position on the autocad "screen" say it was 750x 1000.
When I started the machine, and set the 0,0 , it would fly off in the direction of 750,1000 to start cutting the part !!!!!


So what I do now is to select the part in autocad, click move, click the top right corner and type 0,0,0.
This moved a "known position of the model part" to a known position.

Now when I set the machine zero to say the back right hand coner of the vice, this correponds with the drawing part cordinates.

I'm using MAch3 but its one to look out for if things start going not as expected.

ATB

Derek

[autobionics]

Hi Derek

Many thanks for your reply, Colin1544 also recommended this. I tried setting the datum point as you say but for some reason I still got the same errors and looking at the instruction line in the programme confirmed that the axis was simply trying to go too far.
I then loaded the now "datumed" ACAD file into BOBCAD and this did show that the 0,0,0 point was infact where the machine was referencing it from. Why the ACAD file wasn't changing this I don't know. I then zeroed the BOBCAD part as I did with the ACAD and saved as dxf. When I loaded this file I got yet another error message, something like "not complete" but I cannot remember the exact message. However I gave it up as a bad job and infact created a MDI programme from the ACAD drawing by simply finding the X and Y points at the line and curve intersections. Infact this was so easy, I don't know why I bothered with the dxf file in the first place! Anyway, I will try again as I need to make sure I am doing things right incase I do need to load a dxf file in the future.
I can now say that I have cut my first part on the machine and I am happy with the result. I now need to refine my programming skills and keep trying.

Cheers

Steve