New to 3D printing....

Hey everyone! Im new to 3D printing and excited about getting into this technology. I am a CNC machinist by day and a parts developer by night in the vintage automotive world. I have an aluminum foundry and am involved in patternmaking to create new products. I think the 3D printer can revolutionize my operation and give me a great advantage over my competition.

The gMax printer seems to be awesome with it's huge build platform, and from the videos i've watched, it seems to be very user friendly. One question that I have but never see addressed is this. Because of it huge build platform and potential giant parts you can make at one sitting, I know that at some point you face to possibility of running out of filament to feed the extruder while your making a part. So how does the printer react to this situation? Does it know it ran out of filament or just keeps running? Does it have a default that lets it pause while you add more filament? What if your away on an errand and you come back a few hours later? I've never seen this scenario explained on any 3D printer before and know this is something that has to happen at some point. Thanks in advance.


New Member
It will not know it ran out of filament, so if you calculate that you will not have enough for a print you will need to take action.

What I have done and what I hear most frequently is that when it has nearly run out, pause the print and swap out filament, then resume the print. You'll want to manually feed far enough to not have a gap in extrusion.

There are also ways to join / splice filament. See ... or-prints/ you could splice the tail end of one spool to the start of another, but you'll need a larger spool to hold it all or only do it when it is low enough to add to the new spool.
Ok, so you need to think ahead and keep track of what filament you have used from the beginning. If you do pause it to splice or change spools, does it leave a noticeable glitch or hiccup in the model when it starts back up and resumes printing?


New Member
You can do it by weight so that you can measure it at any time. When you slice a model the slicer will tell you how much filament is required.

I noticed a hiccup in the model the first time I did a swap because I did not feed the filament in far enough. The next time around I actually pushed it far enough it extruded a little bit. It was seamless that time
CNC-Dude, keep in mind also that if you have a dual extruder, you can juggle what's being printed from each spool. If it's factored into your slicing you can use one for infill and the other for perimeters, or switch out at different levels of the print, etc. Also, remember that typically you will not be printing with a solid infill. Depending on what your making you'll use different infill patterns and percentages- typically in the range of 20-40% (think of corogated cardboard). A spool of filament goes a lot longer than you would think....
Depending on deep you get into 3d printing they have alternate firmwares which implement an out of filament command triggered by a limit switch hooked up to your filament. Gordon, or anyone else could probably answer this. How hard would it be to add that feature to the firmware?
I know that Ray is working on an E3D upgrade for the gmax and I think he mentioned something about a filament cutoff switch as well. It may be be something that would address the concerns here.
Thanks for the mention, Chris.

As part of my Cohesive 3D Printer project I'm developing several modular toolheads including a fully assembled E3D extruder module.

I'm offering the fully assembled E3D extruder module I have designed as a ready-to-use upgrade for the gMax. You can get a single E3D for superior performance or 2 identical modules for a dual, allowing multi color/ multi material printing.
The upgrade will simply require removing the existing extruder from the aluminum rail by unscrewing the lower wheels, replacing it with the carriage I provide, and reattaching the belt. Then slide a toolhead into slot 1 and/ or slot 2 and you'll be ready to print in no time. Other toolheads I develop in the future such as paste extruders will be fully compatible with this attachment system.

The E3Dv6 Hotend offers superior printing performance across a wider range of materials and the extruder I have designed around it allows better cooling and flawless printing with flexible filaments, something that the stock gMax extruder struggles with.

I'll be making a formal announcement here soon with pictures, details, and pricing, but in the meantime please do PM me if you're interested or want more details.

Regarding the filament cutoff: I can physically mount a limit switch with roller on it as a filament presence sensor. The necessary modifications to the firmware were made by a 3rd party and I could implement them in the gMax firmware if there was enough demand.

Stay tuned for more details and please get in touch!
I need some help. I just purchased a gmax printer off of ebay new in the box. The assembly went well and the instructions were pretty self explanatory. When it came to the wiring hookups, it totally omits all wiring connections that attach to the wires coming from the power supply under the acrylic build plate(see pic below). The wires for the second box that attaches to the outside of the frame shows the hookup for all the axis', extruders and limit switches just fine. Where do all the other wires hook too? Also, where do you hookup your computer? Thanks.

Rear of box. The instructions don't even show any wires coming out of the rear!


New Member
Most of the wires from the power supply just get bundled up together. There is either a four (4-pin ATX power connector) or six-pin (ATX PCI-e power) connector that will connect to a plug from the electronics box (the one on the outside of the printer you mentioned). I believe there should be only one cable that matches.

You can connect your computer via USB cable to the electronics box (the port is on the opposite side from where all of the wires come out). Then you would control the printer via the pronterface application. The other way to print would be to slice your models and load the gcode files onto an SD card. The SD card plugs in behind the LCD. You can then control the printer via the LCD and the knob.
Thanks, I did find the 4 prong plug-in connector by process of elimination, and was just curious about these remaining wires. I'm getting close to powering it up to start calibrating it and was just being cautious before I plugged it in for the first time.
In your opinion, does the SD card method of controlling the printer offer any advantages/disadvantages over controlling it directly from a laptop or desktop. Thanks again.
Ok, I seem to have the wiring completed. Now the next issue is what seems to be the most common is telling pronterface which Port location i'm using. I went to my Device Manager and found the port i'm using is Port_#0002.Hub_#0004. Of course none of the tutorials i've seen give much detail on how to exactly decipher that into a recognizable "COM" value that pronterface can recognize. It shows up in the Device Manager as "Unknown Device" and asks what driver I have to be able to use it? Thanks for your help, I feel like I am only a few mouse clicks away from being able to do some calibrating and test prints.


New Member
I have not yet printed on my gMax (getting the final parts for Christmas). I have printed both ways on my boss' reprap Mendel, though. Printing via USB affords more control information if you print with software like octoprint which shows the console feedback as it prints, graphs temperature information, layer visualization, etc. Printing via SD card is nice because your computer doesn't need to be there and it doesn't matter if your computer goes to sleep (which can fail a print). Octoprint can also be loaded onto a raspberry pi which also frees your computer from the printer.

The drivers for the board are part of the Arduino software package at under the Drivers folder. Use the arduino.inf file when it asks what driver to use from the device manager you were at.

Calibration and test prints are where things can get interesting. Often after assembly everything seems right, but some tweaks are needed to get those perfect prints. I will do my best if help is needed.
Ok thanks. So another download then for the Arduino software. Just a random question here, I received in my assembly kit a plastic storage box that has the screwdriver for tweaking the potentiometers with, but there is also a computer chip in the box also. What does it go to? Is it a spare for something or does it need to be plugged in somewhere? I haven't seen this mentioned in the instructions anywhere or in any tutorials.

I'd have to see what specifically the piece is, but my guess is that it is an extra stepper driver. There should be 5 of them shipped on the RAMPS board, but maybe it shipped detached.
Ok, I didn't see any additional chips anywhere in any packaging. I have it printing now and am sorting out a few things. How exactly do you set the Z axis stop. I saw a couple of videos where you stick a piece of paper under the extruder tip as you jog the axis down. Once you have a slight drag of the paper, do you adjust the axis stop at that Z height or add some amount of buffer and them set the stop?
After doing several test prints and doing very little tweaking(runs pretty good right out of the box), I did discover an upgrade this I need to perform right off. Learning from my CNC router build, I see the need for a more rigid Y axis platform. Once you get a print that goes beyond where the guide wheels are positioned, the Y axis starts to have a lot of rocking going on, potentially causing the extruder to hit the part as it changes direction. The farther away from the center of the platform you get the more problematic it will become. So I am going to install linear rails and a billet aluminum table to eliminate any flexing at the extreme edges of the table allowing a more stable and flat work surface across the whole area. I am also extending the Y travel a little farther as well. This will not only give better print results because the table will be flat within .001"-.002" all over, but allowing a little greater platform build size.

All in all, I am very pleased with this product and look forward to others doing similar upgrades.
You can take a look hare . While 3D printers still aren’t particularly cheap, there are several that come with a relatively low price tag. We’ve located and thoroughly researched three of the best budget 3D printers on the market so that you don’t have to. Our first recommendation is the MONOPRICE SELECT MINI. At a little over $200, this model is an excellent choice for people looking to dip their toes into the world of 3D printing. Actually I purchased this printer after reviewed this list (, Because they said it's a usefull than other.

It has a 4.7” build area. This isn’t huge, but it’s still large enough to create models or little things for around the home. With a printing speed of 55mm/s, it’s slightly faster than others in this price range. Need a bracket for that cupboard door? No problem, just wait a few hours.
With its WiFi capability, MicroSD slot, and simple, intuitive interface, this product offers far more than you might expect. Plus, its low price makes it an absolute bargain.