[Old-Steve]

Hi. I'm Old-Steve. I am a newbie when it comes to cnc routing. I have two 3d printers, a cartesian and a delta. And I am familiar with xyz coordinates. I bought a tiny hobby grade cnc router. One of the Chinese 3018’s on Amazon. It came with an upgraded grbl board with a little hand held controller.

It has an e stop and 3 limit switches for end stops. They are on the X+, Y-, and Z+ ends. I thought it was weird that there are 3 switches, not 6. I installed the three switches. I added a fourth switch to Y+ because I keep running the bed into the frame there.

I have some kind of homing problem. In the book it said to enter the commands $21=1, $22=1, $23=3. $23=3 inverts the homing direction so after I entered these commands and tried to home the machine, the carriage went the wrong way, away from the limit switches and crashed into the frame where there is no switch. I entered $23=0 and now it homes to where the limit switches are. So that’s better. And yes I put the limit switches where they said to put them. But then I can’t manually jog it or move it after it homes so I never home it anymore because it is useless and wastes my time. What am I missing here? It seems kind of pointless.

It came with a spindle and a laser. I have been experimenting with engraving with the laser. I am getting there. I want to try routing. I read where people didn’t think much about the router bits that comes with these sets so I bought some 1/8” shank bits for it.

I use lasergrbl when I am engraving with the laser. I am using Inkscape and grbl controller when I want to route. Recently I just discovered Carbide Create.
I am having much more success with the laser than with the spindle. But I want to get better with routing.

I think I can route signs and stuff, like a wood router, but I want to try cutting a shape. I have an ABS plastic box (3D printed) that I want to cut a hole in one face. I think I should be able to set a circle, say 20mm’s in diameter, and have the router make multiple passes to cut out the hole. Right? Am I even looking at this the right way?

Let me back up a bit. I am not a machinist but years ago an old guy taught me some stuff on an old Bridgeport mill and a big old lathe. Both were not cnc, just manual machines. I think they both had some kind of auto feeds but I never got that far. I can cut a slot in aluminum or steel, or make different shapes. I am not good but I am good enough for me. I know I can go down a thousandths or two and start cranking x and y. Then repeat until I accomplish what I want. All by hand, measure and repeat. Old school lol.

Finally time for my questions:
What program should I use for routing? I am more interested in cutting shapes and slots and forming, rather than routing or engraving a sign. Can I use a program that will let me route a pattern, then move the spindle down the z plane a thousandths or two then repeat the pattern? And keep repeating until its done. Am I even on the right track here? This is how I would do it 20 years ago on a big giant end mill. I think Carbide Create is more of what I am looking for, but I am kind of lost. Any help and guidance will be greatly appreciated. TIA

 

[old55]

Welcome to the forum.

 

[Old-Steve]

thank you.
and tool paths.
now I have to learn about tool paths.

 

[jw2170]

G'day and welcome to the forum, @Old-Steve ,
Someone with more knowledge on CNC should be along to answer your question.
A few have good programs that have served them well over the years.

 

[gwilki]

Hi Old Steve. I'm Old Grant

Your CAD/CAM/code sender selection will depend in large part on what you want to do with your machine. You say that you simply want to carve shapes and forming. I'm not sure what you mean my "forming". You may want to start with a free program called Easel. You will find it easily on the internet. It will allow you to draw your shapes and slots, then create toolpaths which it will send to your 3018. It is an all-in-one application. It is far from the most feature rich, but it may well do all that you need.

From there, there are many good paid programs. Vectric Vcarve Desktop would be a good choice for your machine. It is not free, but very feature rich. It is not an all-in-one, so you would need a gcode sender to take the toolpaths that it creates and use them on your 3018. I'm a biased Canadian, so I promote gSender by Sienci. UGS is another well-know code sender.

I'm sure that others in this group will be able to provide advice, too. If you have more questions, this is a good place to ask them.

 

[Old-Steve]

Hi Old Grant,
Thanks for all that. I have been playing with Easel a bit. As it turns out not enough.

Forming - like if I had a 20X20X20 block on the screen and I wanted to carve out one corner or a slot. Or maybe a 1/2" diameter shaft that I want to cut a keyway into. Something like that.

I played around some more this morning and found tool paths and I think I am on the right track now. And you're right, Easel may be all I need.

I was going crazy trying to generate an .nc file. It just wasn't happening for me. I think I was stumbling onto some software that would only work with their own propitiatory machines.

I can get grbl controller to hook up to my machine but it wants an .nc file. I installed Inkscape with a g code generator extension and I don't know it sure seems overly complicated for what I am trying to do. So far Easel looks like a much better solution for me.

I think I just pounded one out but I have to wait for the little woman to wake up first. I'm in the next room and well you know...

With my 3d printers I mostly design in Tinkercad, an online 3d modeling program. So this concept of using Easel online is falling right into place lol. Good thing I have a fast and reliable internet connection.

 

[difalkner]

So this concept of using Easel online is falling right into place

Have you tried Fusion 360? The hobbyist version is still free and is quite a capable piece of software. CAD/CAM all in one package with enough Post Processors to choke a horse so there's bound to be one for your machine.

 

[Old-Steve]

I did try Fusion 360 a couple of years ago. It seemed complicated so I went back to Tinkercad.
I'll check it out.

 

[Old-Steve]

I am up and running with Easel.
I just cut my first successful thing.
I set a 20mm circle and told it I had a 1/8" bit and to cut inside of the line.
My first attempt was a little too aggressive.
I slowed down the feed rate to 200 mm/s and the plunge rate to 100mm/s with a 0.5mm depth per pass.
WOHOO! I feel like I am on the right track now.
Thank you Old Grant and everyone.
I'm sure I'll be back asking more questions but I feel like the light went on and I am off to a great start.
Thanks again!

 

[Old-Steve]

well that didn't tale long...
what is step over?
I see percentage rates of 40% and 12%.
Is this like how much the bit will overlap itself when clearing out a pocket?

I Googled it.
Yuppers thats exactly what it means.

 

[gwilki]

Stepover is the distance or percentage of bit diameter that the bit will move when cutting pockets or doing model carving. The smaller the stepover, the smoother the bottom of the cut. If you are doing work where you're not concerned about the finish, go with 40%. If, on the other hand, you are carving a model, for instance, and you hate sanding as much as I do, go with somewhere around 8 - 10%. As you can appreciate, the smaller the stepover, the longer the project will take. However, you can mitigate that somewhat by increasing the feed rate since you are taking off very little material.

Clear as mud?

 

[Old-Steve]

and speaking of feed rate... is 200mm's/m good for a 1/8" bit going down 0.5mm per pass in cheap 5mm thick plywood? I figure there is a sweet spot somewhere between breaking bits and watching paint dry. And I ASSume the smaller diameter the bit is the slower the feed rate should be right? And/or the shallower the cut.
I bought a 4X4 sheet of cheap plywood at Lowes and cut it up to roughly 150X150mm's so I would have material to practice on. Its about 4.7mm's thick.

 

[gwilki]

That's very slow. I'm attaching an excerpt from a chart that the maker of my CNC produced. They tested these specs on the machine that they make - the Sienci Long Mill, so you may want to slow them down a bit until you see how your machine handles them. In general, smaller bits need slower feed rates and shallower passes. Much depends on the rigidity of your machine.

 

[Old-Steve]

Wow you must have a much better machine than my little toy. My bits are 1/8" its more like a dremel lol
I think I will stay slow for now. I'll crawl before I walk.
I just exported a file from my Tinkercad 3d modeling program as an svg file. I was able to import the svg file into Easel. I told it exactly where I want the hole and the orientation and I did it! I feel like I am making progress now. But I am getting concerned about Easel. I have ten more days left in the free trial. Will I still be able to cut after that? I really like the program but there is no way I am paying 24 bucks a month to run a 250 dollar machine.

 

[gwilki]

Perhaps you didn't see my reply to your DM. The "basic" version of Easel is free. It sounds like you are using a trial of Easel Pro, which is subscription based. You may want to see if the basic will do all you want. I suspect that, at least in the short term, it will.