Assistance with CNC G-code generation.

[Drewpan]

Hi All,

My modelling skills are ok and I have been trained to code CNC so I know all

of the principles. The problem is that I do not have ready access to a CNC machine

and so my opportunities are few and far between to practice my skills. I am also

not confident with using fusion Manufacture as I have not quite got my head around

the documentation.

A friend of mine has provided me with a bunch of STEP files for a PC Monitor Arm. I

have "assembled" these files into the finished model to make sure everything is there;

corrected a couple of errors and I am at the stage of converting this model into a

sheet(s) of 18mm plywood for CNC cutout. Problem is I am stuck on how to start it

let alone confident enough to hand him any G-code I have generated to use on his CNC

machine.

I have read the documentation and done the Self Paced Learning but even though I

recognise what is happening, I have not quite made the connection about how it

works or how to do it.

I do want to learn this process and was wondering if someone could step me through

the process and/or provide a video.

What I do know is that the material will be timber. The machine is a Generic 3-axis. If

a dialect of G-code is needed it is GRBL.

Thanks in Advance.

Cheers

Andrew

[Drewpan]

Hi,

Well we will see if this file works. Never had to do it this way before.

Cheers

Andrew

[programming2C78B]

Are you saying you know nothing? What you'd want to do is Nest these parts for one sheet of ply, program it (mostly just 2D contour) and then post it out using the GRBL post. Talk to you friend about what feeds, speeds, and depths work well on his machine. 

youtube will have videos on all of these steps. 

[Drewpan]

Hi,

I know quite a lot about CNC but I am not familiar with how fusion does it. I could sit

down and hand code the program but that defeats the purpose of having a tool that

can do it for you. I am at the stage of I know what I want to do but after reading the

documentation I am still not quite grasping how to do what I need to do. So in terms

of fusion, taking the model through to the creation of the code I do know very little.

Hence my request for assistance to try to learn, using a model I am familiar with.

Cheers

Andrew

[programming2C78B]

I suggest you follow along to some YT tutotials - start with a nesting video to arrange all your parts, then some basic CAM video on creating your setup folder and assigning 2D contour toolpaths. Consider using tabs and workholding. Allow your friend to give feeds+speeds+depths+tooling.

[John_Wright]

Your zip doesn't seem to have any files attached?

Are you wanting to cut them out of a piece of material in one go? 

        if yes - nest them in either a derived model, or manufacturing model then share the model and someone can then show you how you generate tool paths.

        if No - Are they out of individual pieces of ply per part? then you will need to do a single setup per part.

I can't honestly see how the video list below wouldn't give you everything you need for this?

https://www.autodesk.com/learn/ondemand/curated/milling-basics/Rj6KIrcku0M6Km0SRfFyD

In a nutshell though.

CAM needs:

A model (what you want to make)

A setup (contains the WCS for the machine and stock definition)

A cutter (at least one suitable cutter that you can cut the work with - probably an end mill)

A definition of something to cut. (In your case my guess would be a 2D contour taken from the the outside shape of one of the parts)

A post processor to convert the data in the CAM enviroment in G-code

The post process file can then be loading onto the CNC machine usually on a memory stick.

[Drewpan]

Hi,

I don't know what recent changes have been preventing me from creating files that

I attach to forum posts but it is annoying. I used to simply export my file from fusion

and attach it. Here is a STEP file version. Maybe this will work.

Cheers

Andrew

[John_Wright]

Im honestly not just doing this from a step file from scratch for you......

How far did you get with the online training. Screen shots of bits that confused you would help.

In light of not being able to upload a fusion file, can you at least show screen shots of how far you got of anything, at all...

Quite frankly, you are quick to jump on people in the Design forum for not sharing information for not answering questions. So I will ask again.

"Are you wanting to cut them out of a piece of material in one go? 

        if yes - nest them in either a derived model, or manufacturing model then share the model and someone can then show you how you generate tool paths.

        if No - Are they out of individual pieces of ply per part? then you will need to do a single setup per part."

John

[Drewpan]

Hi,

I am fully competent to sit down and hand code the G-code for this project. I have written

sufficient of these programs to not only pass my course but prove I can create fabricated

objects solely using my code. There is a huge difference in having the skills to create

something and being able to drive an automated tool that does it for you. That is what I

am asking for. I have done the research on the documentation and done the Self Paced

Learning. As I frequently advise people in the Design forum. I am also quite willing to help

others in the Design forum. The fact that I do not have ready access to a machine to code

on more often is a circumstance not a weakness. The fact that because I have not had the

opportunity to practice my skills more often is also a circumstance and not a weakness.

The fact that I recognise that I do not have the ability to drive fusion to do what I know it

is capable of doing to a sufficiently high standard where I am confident I will not make

an error and destroy somebody else's machine shows a deep enough understanding of my

own experience and current ability that should be respected not belittled.

I asked for step by step assistance to attempt to learn. Using a file that I was very familiar

with so that I could tie it all together. You then accuse me of being:

"Quite frankly, you are quick to jump on people in the Design forum for not sharing information

for not answering questions."

Would you say such a thing to @TheCADWhisperer who frequently asks people to supply a file

and pictures? I don't jump on anyone. I try to answer their questions and help them out and

have done so for several years now. I also ask questions about why people do things a certain

way to try to learn and make myself a better designer and engineer. I make mistakes and I am

humble enough to admit it. I will also try to answer peoples questions to the best of my ability.

I provided a STEP file to you because it was the only way I have been able to export ANY file to

this forum. On many previous occasions I have Exported my fusion file to fd3 and attached it

to my post. For whatever reason, I am unable to export my file as fd3 for the past few days, it is

not an option. The fusion forum website does not recognise the fdz file I can export.

I volunteer my time to help others on the Design forum because that is what I am most familiar

with. I don't get paid for it. If you think that I "jump on people" then I apologise but I am both

human and on the Autism Spectrum. I do my best to help others. I have attempted to do the

tutorials on how to do this several times and it just isn't coming together for me at present.

If you are unwilling to help then so be it.

Andrew

[programming2C78B]

Are you able to see what Im posting? Why are you not taking the advice I gave you one step at a time and coming back with direct questions if you run into issues? You still haven't even said if its going to be nested or not! 

A diatribe about file attachment means nothing to me when you literally managed to do so in the first message!

[John_Wright]

You seem to have missed my point entirly.

I was saying YOU jump on people for THEM (the op) not providing files.

I wasn't critisizing you for asking for files and pictures on the design forum. 

I was asking YOU for pictures - which we still haven't had!

You still haven't provided any information about the stages of where you got to with the self paced learning. NOT ONE SINGLE SPECIFIC POINT.

Overall:

Well done on learning G-Code 🙂

Having access to a machine is not a requirement of learning CAM. You don't code anything on the machine itself.

You can simulate what Code Fusion has produced in fusion itself, and in a number of online simulators.

At this stage the requirement for a Fusion file seems to be low on the priority list. An answer to one question posed to you would be a start.

I don't get paid for this either......but I do get paid by my company to do CNC machining to produce injection mould tooling - its my fulltime job. (I hate doing the I know what i'm on about line but for this task I really do).

Other than, please answer the questions, I don't know where to go with this....

[Drewpan]

Hi,

Where I am getting stuck is starting and extracting the parts and groups of parts from my

model to do  the machining operations. An example.

Here is the fully completed tutorial about facing a part on a 2D mill. I have finished it. I

understand exactly what it is doing and I have followed the steps to complete the tutorial.

Here is my completed model ready to begin fabrication.

All I want to do to start with is extract this highlighted part from my model and do a

facing operation exactly the same as the tutorial.

But I cannot work out how to extract the part from the model to do this, let alone extract

a group of parts; then auto lay them out; face them all; then individually cut them out of a

single sheet.

I have the skills to hand code this. I understand exactly what I want to do. I am very familiar

with fusion modelling. The fusion Manufacturing however is mainly a mystery because I do

not regularly use it. This is actually the first time I have ever needed to use it.

What I do know is that I have a finished fusion model and I need to take that model and lay

out groups of parts and machine them. I know that fusion is capable of doing this. I know that

fusion will automagically lay out the parts. I know that fusion will automagically generate the

code. What I don't know is how do I take my finished model and actually do it.

I am not asking anyone to do this for me. I am asking someone to step me through the process

to extract and lay out a few parts so that I can get my head around how it is done because I

have not worked out how to do this from the tutorials. Once I know how to do it with say three

parts, I can then go back and do the rest myself.

@programming2C78BI have seen what you have posted but as I said, I am stuck and don't

know where to start. The tutorials I have seen are great for individual parts and I understand

what the tutorials are trying to achieve. I do not have the skills to put them all together yet.

This is what I am trying to learn. No - I do not have the knowledge to follow your simple

instructions.

I know that some of the parts will be cut individually and some parts will need to be grouped

onto  several sheets.

Cheers

Andrew

[John_Wright · Accepted solution]

Okay, that is good information. 

The problem you have is not really a CAM or Manufacturing Enviroment problem. Think of it more of a Design Enviroment challenge (which you are far more familiar with) 

Ignoring CAM completely. If someone tasked you with:

" I have got this completed design that is assembled full of joints and not flat, but I want to lay them out flat on the ground so I can see if they will all fit on my plywood im going to make it from. How do I do this in fusion?"

How would you advise them to solve this problem?

MY ANSWER IS AS BELOW:

I would start with (in the design enviroment):

Start a new file

1. Model the piece of plywood you have as a new component. 

2. Make a new component and use "insert derive" to put the first part in

3. Use a joint to position it flat "inside the plywood" 

4. Repeat until all of your parts (or as many as you can fit) are inside the plywood.

Once you have done this, show us what you have, and we can then show you how to cut it out (if it hasn't clicked for you at this point)

Yes fusion can layout parts automatically, but I think doing it manually would be a better start.

[programming2C78B]

1) Watch some videos on how to Nest parts then
2) You extract the part by only selecting one body in your setup folder. 

Im afraid you're too green for me to want to help you further, as I feel that all subsequent questions will be ones that are simply answered by following tutorials. 

Worst case, program each part one at a time and use a bottom corner as your WCS then just jog to a clean spot on your plywood to cut it out. 

[jeffescott]

I think you must have each part modelled

I think you must have looked at the arrange self help videos etc.

so you should have the parts laid out on the stock in a single set up?

This may be a point of confusion, you say your making it out of 18mm, then you say it is out of timber.

Lets say its a flat sheet of plywood.

parts laid out nicely in a single sheet in one set up.

So do you have parts that need to be machined from the bottom?   If so you will need a second set up.

So now create the pockets, slots etc on the top side.  When those are complete,  create the cut out tools paths. Remember to put in tabs.

Hope fully you left enough stock, so you can pick the piece up and flip it over and still have it dimensionally stable on the real machine.

create neccessary cuts.

Create nc program(s).  
send nc programs to your friend

[Drewpan]

Hi,

Ok here is what I have so far. Sorry for the delay in answering but I have

been busy the last few days.

I think I can see where this is going but I am not 100%.

I also have a question. The Keyboard Top component is 20mm which I did not

realise when I created the model. All other parts are 18mm and I will be using

an 18mm sheet of ply. Since it is only cutting it out and not cutting pockets,

am I better off leaving the top surface aligned with the surface and changing

the depth of cut to 18mm or should I remove it and do it separately? It doesn't

matter if the Top is 18 or 20mm.

Cheers

Andrew

[jeffescott]

Just change your model to 18 mm thick if thats what you want to make

[programming2C78B]

Do a quick push/pull of 2mm to the face, but if you program your Z as the machine table it wont make much of a difference - just a little bit of air cutting to start.