First Build

I'm going to detail the print and assembly of my first build for the GGFlex. Since I have experience building my 3D printed RS-CNC and building my first 3D printing, I should be able to tackle this. My weakest point will be the programming which I will look to everyone else for that. I was going to purchase the kit from ebay, however I went through my inventory of past projects and I already have the bearings, ATmega328P, ATmega16U2, power supply, 2 spare stepper motors, and a host of other things. I will be sourcing the rest of the components myself. Otherwise, a one stop shop for all those parts is a better idea.

Thanks for putting this forum together so the DIY'ers have an opportunity to have their own Ghost Gunner. I currently mill mine with a jig and a drill press.

I think the atmega328p will be underpowered?  That's the proc for an Arduino Uno...

As for control software, my thought would be klipper with a CNC mod: github.com / vladbabii/klippy-cnc (i'm new so i can't post links) should be sufficient for control software, and offloading the thinking to a rpi may make the 328p functional?

I think I'm planning to use one of my two creality mainboards as the brainbox ... i don't see a reason for silent steppers as mills aren't quiet and with the 12mm ball screws the terrible resolution of the a4988 shouldn't matter.

Please keep us updated.

mroberts78641 wrote:

I'm going to detail the print and assembly of my first build for the GGFlex.  Since I have experience building my 3D printed RS-CNC and building my first 3D printing, I should be able to tackle this.  My weakest point will be the programming which I will look to everyone else for that.  I was going to purchase the kit from ebay, however I went through my inventory of past projects and I already have the bearings, ATmega328P, ATmega16U2, power supply, 2 spare stepper motors, and a host of other things.  I will be sourcing the rest of the components myself.  Otherwise, a one stop shop for all those parts is a better idea.

Thanks for putting this forum together so the DIY'ers have an opportunity to have their own Ghost Gunner.  I currently mill mine with a jig and a drill press.

Looks awesome! We're getting a webstore with individual component listings up (in addition to the eBay facing) as well as a community listing space at some point in the coming months, particularly to facilitate buying/selling printed parts and completed machines and assemblies. Let me know if you have any sourcing questions in the mean time!

hardhatpat wrote:

I think the atmega328p will be underpowered?  That's the proc for an Arduino Uno...

As for control software, my thought would be klipper with a CNC mod: github.com / vladbabii/klippy-cnc (i'm new so i can't post links) should be sufficient for control software, and offloading the thinking to a rpi may make the 328p functional?

I think I'm planning to use one of my two creality mainboards as the brainbox ... i don't see a reason for silent steppers as mills aren't quiet and with the 12mm ball screws the terrible resolution of the a4988 shouldn't matter.

Please keep us updated.

The 328P is certainly very outdated but unfortunately it is the only chip supported by DDCut as a PC host until we can bridge that serial USB comm gap. Our first official controller release will likely be a Marlin/RepRapFirmware derivative pair designed to work with with Atmega2560 and SAM chipped hardware.

Affordability and accessibility was our main goal right out of the gate, so simple 3/4 axis 328P boards were also the most reasonable solution for the cost. All of the devs are still running 328P boards, but have also begun fiddling with more advanced options to support the new features we're adding. I've worked with Smoothie for a long time and have a test rig running it. Two of the other guys are getting rolling with Duet2's. We've been using GRBL-Controller for PC hosting for most of development, only starting to fiddle with DDCut about a month ago...

Klipper looks highly capable; the SKR route looks like particularly good value for the money and we'd love to see any insights you come up with in testing it! I have a Pi Zero running EMC2 on a breadboard for an unrelated project that I might swap over to test it as I finish up the 4th axis development.

Thanks for the information. I'd like to know when you get the store open so I can fill the rest of what I need on the BOM.

I am not familiar of Duet2's but I am going to start researching that today. I'm very familiar with Marlin but very curious about the interface with Flex as well as the probing capabilities for proper centering of the 80% Lower. Is there a plan for this?

For my CNC, I use a Z-Probe and limit switches. It seems that Ghost Gunner has the capability of probing 3 locations for centering. I'm sure this will all be worked out by time I assemble this, but curious to start doing research now.

Notes on why we chose the 328p:
-When we began GG development, grbl was only supported on 328p
-To comply with ITAR, GG cannot retain any firearms-specific knowledge by itself. That's the reason we don't have an onboard computer (e.g. raspberry pi)... if we did, then the entire GG unit would be ITAR controlled, whereas right now GG is technically a general purpose CNC machine... it's only the .dd file itself that is ITAR controlled.
-The 328p is more than capable of driving three stepper motors and controlling the spindle. Given the above constraint, there's no reason to invest the engineering effort to redesign the hardware for a new processor.
-We use a custom version of grbl on our machines. You can of course use bone stock grbl, but certain features won't work in DDcut.
-If you want DDcut to support any serial port it finds, contact me (gg dot elt at xoxy dot net) with specifics and we'll add a text string to the config.dd file (that you can manually type in to search all serial ports).

Thank you for that information as I was just getting ready to decide on which board to go with. I'll stick with the 328P and shoot you an email. The software side of it is definitely my weakest area. I'm also in the process of designing a controller box for the back of the CNC so now I know what to size it too.

FYI: The GrBLDC PCB is longer than a standard Arduino shield: 104 x 60 mm
I can't post direct links yet, but you can find the entire PCB here:
github dot com/Defdist/GrBLDC3

Mechanical Assembly complete. I'll be in a holding pattern till more information comes out on the software and electronics side. I'd like to know what everyone else is using on a current working model.

@mroberts78641

I am new to the 3D printing community and saw an advertisement for this on ebay. The 570$ kit looks like it includes everything I need. I just need a definite answer of the efficacy of this. Im about to sell my personal PVS-4 nightvision for it and kinda need a definite answer since I am a starting FFL with limited funds. I know jack s**t about coding but can design and 3D print parts myself in sketchup and (kinda)fusion360. How soon would I be able to make AR15 lowers and engrave them If I bought this?

I went with the cheaper kit as I'm waiting for the G-code to come out before buying electronics. I've built a CNC so I'm familiar with loading Marlin but I'm limited on software knowledge and will need guidance here. I'm also curious on how the Flex will control zeroing out. Whether they plan on end stops or point/touch.

The kit was easy to put together and the 3D file fits everything perfectly. However it's just sitting on my desk waiting for the experts to provide more detail on the electronics, stops, and g-coding.

ThunderKat92 wrote:

I am new to the 3D printing community and saw an advertisement for this on ebay. The 570$ kit looks like it includes everything I need. I just need a definite answer of the efficacy of this. Im about to sell my personal PVS-4 nightvision for it and kinda need a definite answer since I am a starting FFL with limited funds. I know jack s**t about coding but can design and 3D print parts myself in sketchup and (kinda)fusion360. How soon would I be able to make AR15 lowers and engrave them If I bought this?

The setup currently listed on eBay and the one we've been building around for the last month is intended to be plug-and-play with DDCut to support any of DD's projects or content. If you're designing any of your own parts, Fusion is an awesome choice and can output the correct 'flavor' of gcode from its CAM/post processing suite to run GRBL devices. DD's firmware can interface with PC hosts like 'GRBL-controller' without issue and run these jobs alongside any of the official .dd projects hosted by DDCut.

If you're a commercial entity doing any more than a couple of receivers a week, I'd personally recommend going for a proper benchtop milling machine with a CNC retrofit. It has a bit more of a learning curve to get started and will cost between 2-3 times more than the current FLEX kits, but the FLEX is ultimately more suited to prototyping or single part jobs, and the benchtop would provide more long-term value to a smith/manufacturer to make the cost worth it.

That said, we'd love to have more commercial and industry users. We have a number of features in the pipeline to make the FLEX more rigid and suited to duty use, and are always open to suggestions or feature requests!

mroberts78641 wrote:

I went with the cheaper kit as I'm waiting for the G-code to come out before buying electronics. I've built a CNC so I'm familiar with loading Marlin but I'm limited on software knowledge and will need guidance here. I'm also curious on how the Flex will control zeroing out. Whether they plan on end stops or point/touch.

The kit was easy to put together and the 3D file fits everything perfectly. However it's just sitting on my desk waiting for the experts to provide more detail on the electronics, stops, and g-coding.

The current DDCut compatible distribution assumes the same homing/probe methods as the factory machine. Some of our 3DP jigs will have a tool locator switch on the jig itself for relative positioning where required.
The 2.1 release will include parts within its QOL section that have endstop mounts for all axes for a variety of endstop types. Longer term, we're hoping to support both inductive and infrared proximity switches for toolhead-mounted probing as well.

We should have an electronics guide available with 2.1, though the two currently active devs only have 3 different configurations between the two of us and will need more practical testing.

So what exaclty is the atmega328p ? I did not know this was on the complete BoM because I bought the basic version off ebay and totally guessing on remaining parts, but this is the first time I saw "atmega328p " . Is is part of another board or something?

The atmega328p is the 8 bit chip used by the microcontroller that is used in the Arduino.

I'm about to finally get my machine together but i have the same question as a few other people i think. What about the "table", the piece on the x-axis where the jig sits. does the jig span this space or what is required to hold the jig in place?