Newbie needs Advice

[Jenny DavidsonParticipant @jennydavidson44154]

Hi, I’m brand new on this forum, so please tolerate my ignorance. I’ve always been practical and able to use most machinery intuitively, but there are limits to that level of self help. We/ have a tiny milling machine, a Proxon MF 70, to which I’ve attached CNC stepper motors and a controller, which has a USB port for a computer. We have both Mac and a PC laptop available, though I was intending to use a PC laptop for CNC work. So here’s where I need your advice and experience; I seem to need a GCode programme to create designs. Can you advise me on which one to use, please. After I’ve installed it, I don’t know how to program it, so a really good ‘back to basics’ beginners book will help. Can you help with a recommendation? Also, some ready made programs will help because I can use their coding as worked examples. Being naive, I thought that there would be smart software available, which would convert a line drawing to the control instructions in one easy hop – if so, I haven’t found the software yet. My efforts will be exclusively amateur because I’m retired and anyway, my time is shared between too many activities to list. Thank you in advance for your help.

[Jenny DavidsonParticipant @jennydavidson44154]

Newbie needs CNC help

[TomfileryParticipant @tomfilery]

Jenny,

I would strongly suggest that you should do some further online research as to what you need! You have got slightly the wrong end of the stick.

There are three basic stages to driving a CNC machine.

1. CAD (Computer Aided Design) – a program you use to draw the parts you want to machine.

2. CAM (Computer Aided Machining) – a program which takes your drawing file and which YOU tell where and how you wish to machine the part(s). The output of this program is the g code you feed to stage 3.

3. A machine controller which accepts your g code file and drives the stepper motors and spindle on your milling machine.

There are lots of options for each stage of the process. I use, respectively, TurboCad, CamBam and Mach3. Some people use programs which combine the first 2 stages, but a lot depends on what hardware you want to run the cnc machine form (more choices I'm afraid). You don't need to really get into writing g code, but would need to get to grips with the software associated with each stage.

There have been some recent threads regarding choice of cnc systems on here and I'd recommend you search for these and read up on what people have said.

Regards Tom

[JasonBModerator @jasonb]

For ease I would suggest Fusion 360 which will do your CAD design and also the CAM from those designs or imported files from the net and output the required code in many formats to suit your chosen CNC controller. It's free and plenty of video instruction out there to get you started

[Jenny DavidsonParticipant @jennydavidson44154]

Thank you both, and especially for being so prompt in replying, I can’t keep up.

I’ll follow up on your advice and lt you know how I get on. I’m afraid that the priority right now, is making dinner – BBQ.

The workshop job of the day was making a clamp to attach a dial gauge to our lathe tool post, because there are times when stock doesn’t seem to have centred well. The hardware and controller for our mill is all in place, so it’s software next, if tending the allotment doesn’t make first claim!

So much for a lazy retirement.

thanks again.

Jenny

[SillyOldDufferModerator @sillyoldduffer]

G-code can be written manually, and having a go at some simple examples is a good way of improving understanding. NCViewer is an online web viewer than displays what a machine would do, making in possible to practice without risk! (Other simulators available.)

Also study some for G-Code examples, as on this website, try G-Code tutorials, and look for books and reference material.

One thing to watch: g-code varies between machine and type of machine. Milling uses subtractive commands (ie metal is removed to make shapes), whereas 3D printing is based on additive commands (material is squirted to make shapes.) Try and learn with the one you'll be using!

To drive a machine, several choices. Many machines, or CNC controllers, work best with the particular software package recommended or supplied by their makers. Otherwise Mach3 is popular (PC/Mac), or GRBL (Arduino), or LinuxCNC. I leave it to others to comment on their various pros and cons, and to suggest alternatives.

As already mentioned, the best way to write G-code is to generate it with a CAD package. Unfortunately, this requires learning how to model objects in 3D! However, once the object is modelled, G-code is mostly automatic.

I'll mention Fusion 360 and FreeCAD, there are other CAD/CAM packages. In FreeCAD, parts are developed from 2D sketches projected in 3 dimensions to become solids in the 'Parts Design' Workbench. Then G-code is automatically generated from the 3D model with the 'Path' workbench and exported to GRBL or MACH3 for execution. Generation isn't fully automatic because the code generator has to be setup for the target machine (mill, lathe, 3d printer, router, engraver etc) , material, available cutters and whatnot. The workflow is similar in all software tools, but the actual methods and commands vary.

The G-code can be tested with a simulator, and modified manually if need be before metal is cut.

Dave

[Jenny DavidsonParticipant @jennydavidson44154]

Just to clarify.

We’ve already bought and bolted on three Nema 23 stepper motors. We’ve wired them onto a

CNC shield with stepper motor drivers. The controller is already running GRBL firmware. So we don’t really want to start changing any of the items already bought and paid for.

So Tom, have I made a mistake in asking for advice on which gcode program to buy?

I understand the need to set up hardware parameters so that the software knows what it’s dealing with, size of steps, distance moved per step etc and I’m assuming that the program which you recommend will incorporate that setup capability?

A common name found during my searches is Fusion360 for both CAD & CAM programming – shall I just download it and have a look at the setup part first, then turning a visualised shape into a real object. For that I need CAD CAM for Dummies, which doesn’t get many stars on review- so which next?

Jenny.

[JasonBModerator @jasonb]

F360 won't set up your machine, I'll leave that to any GRBL users out there as I use Mach3.

It will produce a design and the g-code in a form that your GRBL controller can understand without you having to actually write a single line of code. Have a read of this.

For the basics in F360 I would suggest looking at Lars Christianson's Vodeos on CAM and CAD

[Jenny DavidsonParticipant @jennydavidson44154]

Thank you Jason,

I followed your link and read the explanation, which refers to ARDUINO which is embedded in our controller, so I’ll download F360, when I get up. I’m writing this on my iPad, so I need to wait until I’m sitting in front of a laptop – probably indoors, with the mill etc connected, because it’s a bit cold outside. Next stop, watch the video.

Jenny

[JasonBModerator @jasonb]

Should probably add that you can import any suitable files for parts that you can find on the net into F360 and do the CAM on those but that is a bit limited to what you can find so being able to produce your own designs will make better use of the machine.

[John HaineParticipant @johnhaine32865]

There are a number of programs that can run on a PC and drive GRBL over usb. There's even one that will run on a phone. For instructions on setting up and using grbl the best place to start is the wiki :

**LINK**

I use grbl but driven from my phone for the x power feed and rotary axis on my manual mill, so I can't really advise which might be best for your needs. From what I can see most will take the gcode from a cad/cam system like Fusion 360 and show you the tool path on the screen then drive the machine. Another place to start is to install the Arduino IDE on the pc and use its serial monitor to type in commands such as the strings needed to configure grbl for your machine and simple gcode to move the axes, just to get confidence that its working.

[Nigel Graham 2Participant @nigelgraham2]

I would add an important point about CAD.

It does NOT "design" anything!

It helps you draw things, and though the most sophisticated makes of CAD hold functions to help you design them, it is still you who does the designing.

You can have all the most elaborate CAD/CAM equipment you like but you still have to know how to make the work-pieces so you can tell it do so.

(I use TuboCAD but all my machine-tools are conventional, aided by a 3-axis DRO set on the mill.)

[Martin ConnellyParticipant @martinconnelly55370]

Estlcam 11 loads drawings in plenty of formats (DXF, PLT, SVG, STL, PNG, JPG, GIF and others) and produces Gcode for a number of controllers including GRBL. It may be simple enough for your needs to get you started. It has a fully functional free trial.

Even though it is not what your ultimate end point you can also put a demo version of Mach3 on a PC and use Estlcam to produce gcode for Mach3 and view the results in Mach3 just to see if it is doing what you intend.

At this stage what may be of use to you is a collection of DXF drawings of some simple shapes such as a circle, triangle and square of sizes that will fit the working envelope of your machine to use for testing and practicing with the software purposes.

Estlcam

Martin C

[Jenny DavidsonParticipant @jennydavidson44154]

Thank you Nigel, I’ll have to be more careful about my wording. I don’t want or need a machine to ‘design’ for me, I’m naturally creative, which leads towards my making unique things, which in turn gives rise to my use of diverse ‘tools’ to turn my ideas into reality. My husband teases me over my versatility in meeting the demands of my originality. Aside from engineering, I’m happy working with modelling clay, fabrics, wood, paint, concrete, glass fibre etc. I won’t claim to be an expert in any area, just a happy amateur. In that sense, I only need to know enough about CNC to get the job done, the outcome being the goal. But I must admit that the learning journey in any area is good fun too.

[John HaineParticipant @johnhaine32865]

Jenny, just to expand my reply and add some context.

CNC systems have 5 components:

1. The machine itself with motor drives to the axes – in your case the Proxxon and its stepper motors.
    
2. A "motion controller" which in your case incorporates the electronics that actuate the motors, which is an Arduino board with CNC shield running GRBL software. GRBL is an open-source, free, slightly basic controller which is widely used on 3D printers and some routers. It takes text "strings" in via USB which include g-code statements (or other statements that configure GRBL with things like steps per unit, maximum feed speed, acceleration and suchlike); drives the motors appropriately, and sends back information on what it is doing such as current axis position. It may be "basic" but it is very useful, and hey, it's free!
    
3. What GRBL calls a "g code sender", a program running on another computer (PC, MAC, Raspberry Pi), that takes a g code file and sends it line by line to GRBL, while monitoring the information coming back such as axis position. It also gives you simple immediate controls such as jogging that allows you to move the machine around with on-screen buttons or similar. Some of these provide visualisation so you can see the "tool path" as the gcode is executed.

   Note that some of the programs mentioned above such as Mach 3 or 4 and LinuxCNC can combine the sender and motion control aspects, as well as providing "wizards" that automate common tasks like surfacing, pocketing, hole drilling etc. There are motion controllers around that can interface to these, needing a "plugin" for the program to adapt to it. Alas neither of the Machs nor LinuxCNC have a plugin for GRBL.
    

4. A CAM program to convert a design into g code.
    
5. A CAD program to capture the design. Some packages like Fusion 360 combine CAM and CAD.

Hopefully you will be able to find a g code sender from the Wiki I posted to above that meets your needs. I haven't yet been successful in loading one to try, but I haven't tried too hard as I manage without at present. (I use an app called Grbl Controller on my phone with a Bluetooth connection.)

I mentioned the Arduino IDE – this is the software that allows you to program the Arduino and debug the code. Though it sounds like you already have GRBL loaded on your Arduino (bought as a package?), it's still a good idea to get a copy of the IDE and use it to test your machine using the serial monitor and, as necessary, update the version of GRBL you are using. The latest version is 1.1h, I am using 1.1f. The IDE is free for download at **LINK** and there are versions that run on PC, MAC, and R Pi – or you can run it from a web page.

Probably quite a lot to read and take in there. It took me a while to get to grips with GRBL (and I'm very familiar with Mach 3) but actually it's a fairly easy program to use. Happy to help further when you have questions.

John.

Edited By John Haine on 03/05/2021 10:47:52

[Michael GilliganParticipant @michaelgilligan61133]

Further to John’s excellent notes:

I have only used it with a 2-axis laser cutter, but Universal Gcode Sender seems to work very nicely

**LINK**

https://winder.github.io/ugs_website/

MichaelG.

[BazyleParticipant @bazyle]

Edit : I think John has filled in some gaps while I was typing.

From SillyoldDuffers (SOD) post it appears that Mach3 and GBRL do the same thing so as the OP has GBRL perhaps any talk of Mach3 is now just confusing the issue.
Also SOD indicated a site for introducing Gcode which should allow the OP to produce Gcode for moving the machine a bit.
So the next useful step would be instructions on how to take a few lines of Gcode from the above tutorial and get it into the controller to see the machine move. Is a CAM program needed at this stage? I'm confused for one.

BTW since you like making stuff research 'machinable wax' making at home to use in testing.

Edited By Bazyle on 03/05/2021 11:12:45

[John HaineParticipant @johnhaine32865]

Mach 3 and GRBL are not comparable at all. Mach 3 does incorporate a motion controller if used with a PC parallel port, but is a very old and unsupported program and PCs with parallel port are also very old. GRBL is a motion controller as I said above, it doesn't have any of the features of Mach 3 other than the motion control bit (if you use it). It would be great if Mach 3 had a GRBL plugin but there isn't one. As you say, except for comparison purposes talking about Mach 4, Mach 4, or LinucCNC is just confusing the issue now.

The best way to take a few lines of g-code and test the machine moving IMHO is to use the Arduino IDE and serial monitor. It needs a few config commands as listed here:

**LINK**

Basic things to set up are steps per unit, maximum axis speed, axis acceleration, max travel (if soft limits are enabled). There are a couple of things to set on the hardware too such as microsteps on the motor drivers which are needed to define the steps/unit. May also need to set axis direction depending on how the steppers have been wired. Each parameter is set typing a command into the serial monitor window such as

$100=250.000 then press send

for X steps per mm. Once set these are stored in the Arduino and don't need re-writing unless you want to change them.

Then a command such as

G00 X10 Y20 Z25 <send>

will move the axes by 10, 20, 25 mm respectively. If this works then basically everything is OK and you can start sending code from something like UGS.

Michael, thanks for pointing me to UGS, it looks useful and actually installs very easily. Martin, Estlcam also looks useful. I would love to move on from Mach3!

[Martin ConnellyParticipant @martinconnelly55370]

Jenny I have sent a few sample text files, check your inbox.

Martin C

[JasonBModerator @jasonb]

Posted by Bazyle on 03/05/2021 11:03:22:

So the next useful step would be instructions on how to take a few lines of G-code from the above tutorial and get it into the controller to see the machine move. Is a CAM program needed at this stage? I'm confused for one.

Depends how you go about it, I would ask is there any need to learn g-code first? All the stuff I have done I have not written a single line of g-code. It was the talk of G-code that put me off having a CNC when the chance came up earlier and watching guys on the SMEE stand take ages to type out and machine something I could have done manually in a fraction of the time. In a similar way John in his Shapeoko thread has been straight up and running drilling and milling without typing any G-code.

Jenny is your aim just to do simple 2D work eg cut a shape from flat sheet or do you want to do full 3D wok where the shapes are far more complex and have the third vertical heights changing?

[Jenny DavidsonParticipant @jennydavidson44154]

Thank so many of you for taking to time to help. I just can’t keep up. Jason, I watched the link which you sent me, which makes the process of building a 3D model using F360 very clear. John too, you explanation of the relationship between stages is enlightening. I can’t keep up.

I’ve had a busy day including prepping a venison casserole along with allotment rhubarb with orange and ginger for desert/dinner. That’s life I’m afraid, hobbies when time allows.

For those of you who are reassuring me that I don’t need to write code – yippee. I was involved in computer prototyping in the 1970s. Back then machine code was needed, then assembler, then higher level languages, so I’ve served my time and I don’t want to wind the clock back.

to answer your question Re 2 or 3D. The answer is that I don’t know. As with all technology, once we get started, we can start to see new opportunities. My husband runs a pétanque team, with a monochrome eagle’s head as their emblem. It comprises of several elements, not just an outline so I might try engraving it onto a two layer laminate as a first project. But what about a three layer form from solid stock! How about engraving seed types on slate markers, then 3D vegetable markers in hardwood to mark full size crops. I’ve tinkered with a stainless steel contemporary tree to hang our bird feeders from. Suppose I engrave motives to tack weld onto the curved branches – stainless steel = v hard, yes I know.

A friend gave me some small pieces of exotic hardwoods a while ago, lignum vite, ebony etc, which I cut into facets for decorative key fobs. How would a 3D tree cut into ebony look? Or a church into Yew, or as an advanced project, a pair of holly leaves with berry’s in 3D because our house name is Holly Corner.

There’s a model steam engine (stationary) in our workshop, just started, so there must be a CNC opportunity there somewhere.

Overall, I’d like the flexibility to move onto more sophisticated designs, once I’ve learned the basics. As ever, current capabilities limit what we can do – a fourth axis beckons. But for now ** when I find the time.

Thanks again

Jenny

[Phil super7Participant @philsuper7]

Jenny have a look at vectric cad/cam packages very well supported Link Here vectric.com

[Anonymous]

While one may not normally need to write G-code I'd assert that a basic understanding of the types of functions, their operation, and the common commands is useful. Especially when things don't go according to plan. Although rare CAM systems don't always generate G-code that reflects the toolpath shown. I'd concur with SoD that a G-code backplotter is essential as a sanity check – I use NCPlot.

A basic understanding of G-code also helps in writing a post-processor – essentially macros that configure the specific machine and how it implements various commands. It's safe to say that G-code is a non-standard standard.

I only written one G-code program by hand, to implement helical features which my CAM program wouldn't do, so when needs must.

Andrew

[Jenny DavidsonParticipant @jennydavidson44154]

Posted by Martin Connelly on 03/05/2021 12:38:27:

Jenny I have sent a few sample text files, check your inbox.

Martin C

Thank you Martin. For now it looks like code from the enigma machine to me, but let me sit on it for a bit and I’ll come back to it.

Jenny

[Tom SheppardParticipant @tomsheppard60052]

One of the nice things about UGS is the visualiser which shows what you actually asked the tool to do rather than what you thought it was going to do. Use that and a standard text file to refine your design and you will learn a lot as you go along.

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