Chapter 4 Design and Workflow options
Designing a cut-file and generating g-code is the goal of the work flow. A computer aided design (CAD) program or a vector drawing program can be used to create new designs. Once the design is finished, it must be translated to machine locations and speeds to create the cuts. A computer aided manufacturing or CAM program makes this translation. The translated file is made up of lines of text called g-code. There are several options for going from idea → CAD → Cam → gcode → Web Control → Arduino / Maslow → product (could be makerverse instead of webcontrol). The software options are varied in capability, price, and ease of use. Some are web-based with cloud storage while others are commercial packages or even open source and available for free. Choosing a design path is typically influenced by prior design experience or lack thereof. If you are selling your creations, then you have fewer options that are free.
Options for creating drawings:
-
Vector drawings (SVG)
– trace jpg or screen shot
– draw a scalable drawing
Programs:
a. Corel Draw
b. Inkscape
c. Blender
d. Adobe Illustrator -
Drafting program. Create dimension drawings (2D is all that is needed) saved in dxf or exportable to svg
a. Fusion360
b. FreeCAD
c. Sketchup (suggested by-youtube video)
Once the drafting / drawing design work is done, the image needs to be translated to gcode that maslow can process to know where to move and cut. This is the CAM portion. CAM does a couple things to output usable gcode. It is best to quote
Maslow supports GRBL gcode. To get GRBL code from most of the CAM options, once must specify the correct “post processor,” (the software that will be processing the gcode after it is written). Where noted and mentioned by users, those post processors have been named for reference and possibly linked for a more in-depth review if desired.
There are several options for creating gcode. There are paid options and free options such as:
- Easel (web based - many use it
- EstlCAM (MetalMaslow distributes full version)
- Carbide Create (free with pro version to be released soon)
- jscut open source java server
- DXF2GCODE (free)
- krabzcam (forum link)
- Onshape and kiri:moto (forum link)
- NC corrector
- Vcarve
- CAMworks
- MakerCAM (runs in flash and is dying because flash is no longer in use - if you want to use, try IE)
Some tools allow you to preview a simulation of the cut such as Camotics, carbide create, and estlecam to name a few.
Some of the drawing/drafting programs have integrated or installed extensions that will allow gcode creation from the same design program:
- Blender
- FreeCAD grbl post processor
- Fusion360
- Inkscape - “gcodetools” extension and postprocessor setting is none.
- there have been some posts on using sketchup, but not many.
The point is that there are many options and many opinions. Some trial and error is likely required to find a software set that works for your desired work output and tolerance requirements. The more artistic vs the more engineering user may require a different feature set for dimensions or layering. Your mileage may vary and your preferences or previous use may influence your decision more than the output. In the end the goal is to generate gcode the maslow can process to move and cut.
Knowing your bit size when making the design helps visualize the finished product. Some software will allow you to cut inside, center or outside the traced line, other programs allow you to set the line width to the bit size, so you see the finished product size. Generally speaking a 1/8" bit with a 1/4" to 1/8" adapter in a 1/4" collet or a 1/4" bit in a 1/4" collet will work. If you have a smaller bit, the rotational speed can be higher, but generally the spindle speed is at the lowest setting. An upcut bit will leave more top-side fuzzies than a down-cut. Spinning too fast will dull the bit and has a greater chance of fire. It has been mentioned that the best cutting removes chips of wood, not fine dust. The commonly accepted approach for cutting is to plunge the bit half of the diameter for each cut pass. For example. When cutting 1/2" (12.7 mm) ply, the plunge might be 1/16" (~1.5 mm) with a 1/8" (3.175mm) bit for a total of 9 passes and overshoot by 0.8 mm. A 1/4" (6.35 mm) bit would cut 1/8" (3.175 mm) per pass for a total of 4 passes and unless slightly more might not fully penetrate the work piece if the z axis is zeroed slightly high. These passes can be run at a feed rate of up to 30-32 ipm (762-812 mm/min). These recommended numbers will provide reliable cuts, but will take what may seem like forever to complete. Some report success running at plunge depths of 2x the bit diameter, but with a slower feed rate. If the cuts are excessively fuzzy, it may be time for a new bit. If the cuts are jagged, the bit may be moving too fast for the material or plunged too deep. All material can be optimized and does not cut the same. Solid oak will cut different than acrylic, which will be different than 3/4" ply or mdf. Test and success.
When ready to cut, it is time to chuck up your bit: upcut, downcut, single flute, dual flute. Zero your z axis, set your home position (“workspace home” in makerverse or home in webcontrol) so your cutout will be on the work piece, and press go.