When replacing or upgrading your K40’s controller, how do you choose the right option for you? In this K40 controller desktop review, we cover your options.
You are here… M2 Nano board
Our K40 controller review starts with the M2 Nano board which looks like this.
It is the standard controller that ships with each K40 laser. It’s just a motion controller which has not been integrated with the K40’s digital control panel for laser power.
- It has very limited control of cutting in corners, which is likely to result in burnt corner points
- It provides only dither-mode engraving. This simply means it can only switch on/off at one set power level, so you miss out on the improved images that gray-scale engraving brings
- It’s expensive for what it is – outdated technology
- It runs an unknown propriety form of G-code, making it hard to work with. The work-around is to use theK40whisperer software which emulates the proprietary G-code so that your K40 can be accessed by software other than MoshiDraw / LaserDraw / CorelDraw.
Things that matter
Before we step through available controllers in this K40 controller review, let’s be clear on what factors matter….
- Ease of upgrade (the technical effort and complexity)
- Engraving and cutting speed
- Quality of the engraved images – gray scale looks better than dithering, and 16 bit is much better than 8 bit.
- 3rd-axis capability – for some users, the ability to control a Z axis table or rotary via G-code can be important
- Support – some products have no support, and you’re reliant on the goodwill/knowledge of the user community. You may prefer a product that has dedicated support provided by the vendor.
- Overall Cost
Details as known at time of publishing.
For those interested in the technical details, this section is for you. If not, skip to the Summary.
One of the key differentiators between controllers is their dialect of G-code. One kind is Grbl, an open source firmware. Smoothieware and TinyG are open source firmware derived from Grbl. Both provides G-code motion and laser power control.
DSP based controllers use G-code as input, but are expensive specialized circuits that really belong in their own category.
The K40 controller review list:
Mini Gerbil: a recently designed replacement to a successful Kickstarter project. It uses a powerful (but cost effective) 32 bit Arm processor called STM32. It uses Grbl. The Mini Gerbil has dedicated firmware which optimizes the PWM, speed profiles and the USB communication. It comes in a neat little case.
Super Gerbil: a successful Kickstarter project offering up to 5 axis control for CNC, but is also applicable to lasers. Has all I/O coupled via opto- couplers to reduce electrical interference and noise. Also based on the 32 bit Arm processor STM32 . Uses Grbl. The Super Gerbil has dedicated firmware which optimizes the PWM, speed profiles and the USB communication.
Cohesion3D: these boards are based on the 32 bits LPC1768 ARM processor (dating from 2008). This board runs Grbl and Smoothie, comes with an SD card, display and Z-axis control. Unfortunately, at the time of writing we haven’t found specifications about the PWM resolution and speed.
TinyG: TinyG boards are based on the 8 bits AVR xmega192a3 processor but there’s limited information available. The board runs TinyG which has been derived from Grbl. Unfortunately, at the time of writing we haven’t found specifications about the PWM resolution and speed.
Arduino/Eleksmaker: these boards are based on the Arduino 8bits AVR processor. Their main disadvantage is the 8 bits PWM provides limited levels for laser power control – you won’t get quality gray scale engraving. Uses Grbl.
RUIDA DSP is a digital signal processor board used in the more expensive Chinese Lasers, offering faster motion and laser control than the Nano M2 board. The Ruida DSP controller comes with RDWorks, a CorelDRAW derivative. The only other working software we know of is LightBurn, but be prepared to spend more for the DSP specific version.
The comparison table reveals a large disparity in value. We suggest the following should be dropped from further consideration:
- the M2 Nano controller – fewer features than cheaper alternatives, with the added disadvantage of limited software being only CorelDraw and Laser Draw.
- DSP – their traditional speed advantage is under threat from the new generation controllers, and they have no other stand out features to justify their extreme cost.
Meanwhile, Arduino and TinyG lag on features. Arduino may work for the very low budget option if you’re prepared for some fiddling without dedicated support, whereas the TinyG doesn’t compete well at all in its price range. Oh, and don’t forget that Arduino’s hardly a speed machine.
Among the remaining, Mini Gerbil is a clear winner in the 2 axis stakes. In the battle for 3 axis controllers, Super Gerbil is a newer, better value product out-staging the older Cohesion 3D.
What have we missed ?
We’ve tried to simplify a relatively complex decision, and this may not take into account everyone’s needs. Who knows, maybe there’s someone out there who actually like CorelDraw ! Seriously though, we see a lot of interest in engraving, but if you’re a cutting-only guy or gal, this could change your best choice.
We didn’t review CNC related boards like PlanetCNC since we have no evidence that these boards are used in K40 laser machines.
If we’ve missed a decision factor of interest, or the summary isn’t quite complete, let us know in the comments below. We’re happy to update the table and blog.
Pssst, have you heard…
It’s no secret we sell the Gerbil products that topped this review. And it shouldn’t be a surprise they’ve come out on top – we purposefully designed them to address the gap between Arduino’s poor performance and features, and the poor value/features of the other products.