Romaxx CNC :: Frequently Asked Questions
What is an "MPG"?
MPG stands for Manual Pulse Generator and is basically an electronic hand-wheel. It's the silver dial
on the front of the machine in the picture to the upper right. By selecting it's function in Mach3, when
the user rotates the MPG it moves the selected axis. It has 100 detents per revolution and each
detent or hash line equals approximately .001" of linear movement. It is an asset when referencing
the cutter to the work and a neat way to jog the spindle around.
What is meant by "closed loop"?
This option adds a level of insurance to the system with regard to positioning accuracy and reliability. It includes incremental
rotary encoders for each stepper motor along with interface board for easy connection to your PC.
Stepper driven machines operate in what is referred to as an open loop configuration. That is to say, a motion command is
executed by the software and the hardware is expected to carry out that position without checking it. In a closed loop
configuration, the hardware senses position with an encoder and feeds this back data back to the software for verification,
thus, closing the motion loop. Should the physical position get out of synch with the logical position by a specified amount, it
will trigger a software "Reset". This will prevent further damage to expensive work piece materials such as Ebony, Teflon
plastics, etc.
It should be noted that open loop systems can be very reliable and have been used throughout industry for many years.
Can I put a different table on my machine?
Yes! We opted for MDF as a good basic table that is flat and very inexpensive to replace. It just bolts to the upper surface of
the machine base. As is the case with many routing operations, the cutter may extend through the workpiece into the table’s
surface. It is because of this that most users prefer to attach an inexpensive table surface as a spoil board to be thrown away
when used up.
What is the best way to hold my workpiece to the table?
There are countless methods of doing this. What we found to be the easiest for most work is just
two-sided carpet tape. Of course, a better means is to mechanically hold the work, with a vise or
clamps, etc. A vacuum table could be used as well, made with some MDF and a shop vac as a
vacuum source. When using an MDF table you can screw right into it, to hold fixtures, vises,
vacuum- tables, etc. The cast aluminum table options with tapped and reamed holes makes this
much easier.
What type of maintenance does the machine require?
Other than keeping it clean of sawdust and not letting it build up on the rails, etc. The machine requires no scheduled
maintenance. All the bearings are sealed and lubricated. The few bushings it uses are oil-lite bronze and require no
lubrication. We designed it with as few moving parts as possible and every component was selected with long service life
and low maintenance operation in mind. The timing belts are very high quality steel lined poly. We have one older CNC
machine in our shop with just neoprene glass lined belts that are 30 years old, still working fine and was the inspiration
for this machine design. All the timing pulleys are high quality machined aluminum, again, requiring no maintenance.
What does "ready to run" mean?
It means the machine is ready to take out of the box, connect it to a PC's printer port and operate it as a 3 axis CNC platform.
We don't include a spindle, as many folks have a preference to the type of spindle they want to use for the specific type of
work they are doing. Some customers use the Romaxx for rapid prototyping with a syringe type injection head while others
maybe using it for a 3D digitizing system with a probe.
The Ryobi panel router that we offer as an option is a good candidate for general woodworking and
plastics machining. It's 3/4 horsepower and accepts standard 1/4" router bits.
What is the work-flow? How do I get from idea to machined parts?
This is a very common question and there are many available software products to complete this process. It is essentially
three basic steps, just remember, CAD-> CAM-> CNC.
The design phase, putting your idea on the screen, is done in a CAD program, and this can be any CAD software that will
output a file format that a CAM type software can interpret. Common types are DXF and IGS formats.
Once a drawing is completed and exported in DXF perhaps, it is opened up in a CAM type program like "Sheetcam" or
"Meshcam". This is where the actual G-code generation takes place. G-code is the common term for the programming
language that the CNC controller reads and converts into motion. Once the G-code is generated and saved, it is then loaded
in Mach3 and ran.
Folks that are proficient with the above process can do simple parts in less than a minute and have the machine ready to go.
There are many different software packages available. Some like "Bobcadcam", are 3D CAD and CAM integrated together in
one suite. Mach3 also includes L-CAM for free to use and supports 2.5 D tool path and code generation and supports DXF
import. Some people even code parts by hand. Knowing the commands and not minding the math involved, it is a popular
means of producing G-code.
Newfangled Solutions' offer a suite of "wizards" for Mach 3 that tackle common tasks such as hole patterns, pockets etc. Some
of the more basic wizards are already included in Mach3 for free. This is one area where the "best" method to use is whatever
works with for the type of work that is being performed. Download some demos and play with them and see what you like.
I'm new to CNC, can you assist me a bit if I need it?
Sure, we are always just an email or phone call away. Our e-mail is monitored closely and you will receive an answer to your
question in prompt order. We don't offer training, but we will assist you in making your CNC machining experience a
success. There is a wealth of information on the web such as, , this is the website for Mach3. There are
instructional videos available for download as well as an reference manual.
Like most software companies, Bobcad offers training materials for their products, along with many support groups on yahoo.
All of these are an excellent resource for learning CNC machining techniques. But, should you not be able to find an answer,
contact us.
What is G-code?
G-code is essentially a standard machine language whereby NIST standard G commands are given and interpreted by the
CNC controller. Below is a basic run down of how a part is drawn and the subsequent code is produced.
First: The part is drawn in the cad program. Then tooling offsets are applied, in the case below the tooling offsets are .125"
and depicted in red with arrows showing the direction.. The black lines are the actual part.
Second: The CAM side of the software is opened and the tool-depth settings are called out.
Third: The G-code is generated and saved in a text file
with a .tap extension.
Below is the G-code that was produced with some explanation of each line and what it represents:
N1G40 <--- Cancels cutter compensation (default entry)
N2G80 <--- Cancels Canned cycles that may have been running previously
N3G90 <--- Absolute Coordinates ( All moves are from one X and Y point of reference)
N4G54 <--- Default fixture offset
N5 G00 Z0.1 <---Safe rapid plane above zero
N6 X2.5764 Y-0.9177 <---Moves to position
N7 G01 Z-0.0333 F5 <---- Z moves down .033" below the part surface
N8 G03 X2.8514 Y-0.6427 R0.275 F30 <----Now the cutting begins on the oval
N9 X2.5764 Y-0.3677 R0.275
N10 G01 X1.5764
N11 G03 X1.3014 Y-0.6427 R0.275
N12 X1.5764 Y-0.9177 R0.275
N13 G01 X2.5764 <-------First pass complete
N14 Z-0.0667 F5 <-------Z moves down another .033"
N15 G03 X2.8514 Y-0.6427 R0.275 F30 <-------Cutting resumes on the same oval
N16 X2.5764 Y-0.3677 R0.275
N17 G01 X1.5764
N18 G03 X1.3014 Y-0.6427 R0.275
N19 X1.5764 Y-0.9177 R0.275
N20 G01 X2.5764 <---- Second pass complete
N21 Z-0.1 F5 <-------Z moves down the full .100" depth
N22 G03 X2.8514 Y-0.6427 R0.275 F30 <------Cutting of oval resumes and is the last pass
N23 X2.5764 Y-0.3677 R0.275
N24 G01 X1.5764
N25 G03 X1.3014 Y-0.6427 R0.275
N26 X1.5764 Y-0.9177 R0.275
N27 G01 X2.576 <------- Oval is now complete .100" deep
N28 G00 Z0.1 <--- Z retracts to safe rapid plane .100 above part
N29 X4.4453 Y-1.1478 <----- moves over for circle
N30 G01 Z-0.0333 F5 <----Z extends into work -.033"
N31 G03 X3.4953 R0.475 F30 <--- performs circle path 3 times and successively deeper passes
N32 X4.4453 R0.475
N33 G01 Z-0.0667 F5
N34 G03 X3.4953 R0.475 F30
N35 X4.4453 R0.475
N36 G01 Z-0.1 F5
N37 G03 X3.4953 R0.475 F30
N38 X4.4453 R0.475
N39 G00 Z0.1 <----Circle finished, moves on to perimeter.
N40 X-0.125 Y0.
N41 G01 Z-0.0333 F5
N42 G02 X0. Y0.125 R0.125 F30
N43 G01 X5.
N44 G02 X5.125 Y0. R0.125
N45 G01 Y-2.
N46 G02 X5. Y-2.125 R0.125
N47 G01 X0.
N48 G02 X-0.125 Y-2. R0.125
N49 G01 Y0.
N50 Z-0.0667 F5
N51 G02 X0. Y0.125 R0.125 F30
N52 G01 X5.
N53 G02 X5.125 Y0. R0.125
N54 G01 Y-2.
N55 G02 X5. Y-2.125 R0.125
N56 G01 X0.
N57 G02 X-0.125 Y-2. R0.125
N58 G01 Y0.
N59 Z-0.1 F5
N60 G02 X0. Y0.125 R0.125 F30
N61 G01 X5.
N62 G02 X5.125 Y0. R0.125
N63 G01 Y-2.
N64 G02 X5. Y-2.125 R0.125
N65 G01 X0.
N66 G02 X-0.125 Y-2. R0.125
N67 G01 Y0.
N68 G00 Z0.1 <----- Perimeter and part complete, Z retracts to safe rapid plane.
N69M30 <----This ends program, shuts off all outputs, and rewinds program to the beginning.
Click here to download this actual Gcode Program that can be loaded up in Mach3 for a real time demo:
Romaxxexample right click "Save target as"
Another useful method of learning code: Load up the above code in Mach3 and then select the "Single" button on screen.
Then each time the "Cycle start" button is pressed it will only execute one line of code. Watch how each line is represented in
the toolpath window, one at a time.
My laptop doesn't have a parallel port, can I use a Parallel port adapter?
The quick answer is no. Most of those adapters are USB connections. Typically USB is too slow for CNC control. A real
parallel port, is about 25 times faster transfering real-time data than a USB. However there is a PCexpress type parallel
adapter that is reported to work for some. Of course the laptop must have a PCexpress port. USB or ethernet? No
Can I run my Romaxx from a Laptop computer?
It depends on the Laptop itself. Some will work and some won't. It depends how they handle system timing in regards to
battery save features etc. One quick way to find out is run the "Drivertest.exe" located in the C:/Mach3 main folder. It should
produce a thin line down the center of the graph, with an occasional spike. If it's a broad black line, it's a safe guess that the
computer has very unstable timing and will not be a good candidate for machine control. Good practice is to use an standard
old desktop with a 1Ghz or better processor and make the PC dedicated to the task. In other words, no internet connection,
no other computing at all except running the machine. There is even an app called "PClite" available on the web that strips
down windows for very smooth operation. It shuts down all processes for multimedia devices, some of them can be a bit
demanding from a CPU timing standpoint. There is also a document available from Artsoftcontrols called "Optimization.txt" that
is a guide to turning off uneccesary processes.
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We offer as well the Vectric line of products here. As well as Moi3d here. A good combination is Moi3D for 2D and 3D CAD
design and the Vectric Cut2D and Cut3D for the CAM operation. Vectric and Moi products have been "hand-selected" for our
Romaxx customers due to their user-friendliness, speed and power.