Fine-tuning & Increasing Performance of your gMax Printer

Post your own questions and topics to troubleshoot common problems with the gMax printer as well as similar printer designs.

Re: Fine-tuning & Increasing Performance of your gMax Printe

Postby PianoPrint » Mon Jan 30, 2017 2:10 pm

flrock wrote:
PianoPrint wrote:The multiplier is changed in S3D and the firmware is downloaded from the PC to the Ramps 1.4 through the Arduino interface. You save the multiplier into the profile of S3D exclusively for each brand and type of filament.


Just so I am clear. I command 100mm to be extruded, it actually extruded 88mm. That gave me a number of 1.13 is this what I am to add in the multiplier in S3D? If so, why would I need to multiply it by 96 steps/min?



Did you use this formula?

S= Steps
S=((What we asked for) / (what we got)) x (existing steps/min)
Example if your extruder measured 99.51mm and you asked 100mm then:
S=((100 mm )/(99.51mm)) x ( 96 steps/min) =96.47 steps/min

What are your current steps/min of your extruder?
These users thanked the author PianoPrint for the post (total 0):
PianoPrint
 
Posts: 45
Joined: Tue Aug 04, 2015 2:37 pm
Has thanked: 0 time
Been thanked: 17 times

Re: Fine-tuning & Increasing Performance of your gMax Printe

Postby PianoPrint » Mon Jan 30, 2017 2:13 pm

Did you go through the process as explained in the section that was posted earlier in the this thread?

4. Extruder Filament Calibration – Extruded Length

I'm asking so that I can understand which part I can explain better in order to get you going.

Let me know.
These users thanked the author PianoPrint for the post (total 0):
PianoPrint
 
Posts: 45
Joined: Tue Aug 04, 2015 2:37 pm
Has thanked: 0 time
Been thanked: 17 times

Re: Fine-tuning & Increasing Performance of your gMax Printe

Postby PianoPrint » Mon Jan 30, 2017 2:48 pm

Here is an example of using a 3% infill, 0.20mm layer height no internal support printing with red PETG. Personally I am very impressed with the results. Keep in mind the circles that you see on the surface of the print were present in the CAD model. So what you see on the model surface is the actual detail as intended. I could never imagine this type of quality when I first put the printer together. Now I am incredibly happy with the results.
These users thanked the author PianoPrint for the post (total 0):
Attachments
IMG_0360.JPG
IMG_0359.JPG
IMG_0358.JPG
IMG_0355.JPG
PianoPrint
 
Posts: 45
Joined: Tue Aug 04, 2015 2:37 pm
Has thanked: 0 time
Been thanked: 17 times

Re: Fine-tuning & Increasing Performance of your gMax Printe

Postby oneaday » Wed Feb 01, 2017 3:01 am

PianoPrint! +Rep for this thread! I hope to be able to add some more knowledge when possible.

Im still tuning my gCreate to output a good quality for me. I've been into 3D printing since 2010, at first the powder typ printers from zCorp, and the last year I've been printing 24/7 with two Prusa i3 MK2 (BETA - testing the multi color upgrade on one of them), so I see myself as experienced with 3D printing, although there are four things with the gCreate gMax that I'm still struggling with, I would be extremely happy if you could give your short view on this matters.

1. First layer / Start of print


On the prusa my process are: Slicing with 80-100% first layer height for 0.2mm layers
When the printer starts i turn down the speed, and use a Live Adjust Z feature which gives me the possibility to change the Z offset, to get a good squeeze for PLA (or less squeeze for flexible filaments for example). When its set I can print prints after prints since the Live Z adjust is stored. If I switch filament type I might need to slightly adjust it.

When I got the gCreate I downloaded the profiles and I was chocked by the first layer settings in S3D, extreme over extrusion! The first tests looked like a mess honestly. I understood after contact with the support that it's a way to handle un-flat spots in the acrylic plate which is the default plate, so I started to tune the settings closer to what I'm used to.

I always need to adjust the Z offset with babystep Z at the start of the print, even though Im at 100-150% first layer height. Otherwise it will pretty much drag the nozzle. Also I still think the first layer is crazy over-extruded I'm not even close to the perfect, smooth first layer that the Prusa achieves. Also having some issues from time to time with adhesion, and if I print an object that covers either front-back or left-right side of the bed, it can be too squeezed in the front and not sticking in the back. Sometimes not sticking in the center, but squeezed in the back/front. Havnt been able to reproduce this, I'm just moving the print around, restart, adjust Babystep Z until I get a complete first layer.

I think I might need to lower my BLTouch just a bit (half of a turn on each screw?), so I will probably do that as the next step. I will also calibrate the extruder to see how off I am. I've settled on the Colorfabb Economy PLA and Colorfabb NGEN for 80% of my prints, so I'll calibrate for both of those.

If you have any other idea or tip regarding the first layer please let me know!

IMG_1319.jpg



2. Surface finish


I cant say that I'm satisfied with the surface finish of the prints, it doesnt matter if I print at 0.2mm layers or 0.38mm layers, i see a lot of horizontal lines, ringing/ghosting etc. Attaching example image (0.2mm layers, speed 30mm/s)

I have adjusted my Z axis (had to loosen the bolts holding the X axis parts that connects the X axis to the Z rods to be able to move it all the way up without skipping) and X axis (had too adjust the eccentric bolts a bit to get a smooth X movement.) And I'm printing slow in general.

I'm printing a lot of 3D hubs orders, and I cannot use the gMax for that yet because of the poor surface finish I'm getting.

Groot printed with 0.36mm layers, the first image 0.2mm

IMG_1568.JPG


IMG_1566.JPG



4. Nozzle drag / Vertical Lift not working?

Especially during the first layers I'm experiencing some heavy nozzle drag when the nozzle moves from one side to the other (typical retraction moves to me), but it seems like the Vertical Lift doesn't work like I'm used to. This problem is enhanced by the over extruded first layer but the nozzle does not lift when it should (imho). I've tried Vertical lift from 0.5mm to 2mm without any noticable difference. After about one month of printing, and many prints I've seen a Vertical lift ONCE, after finishing some supports, but that's the only time I've actually seen it. All I hear from the printer is the nozzle scraping when doing retraction moves. This brings us to the next issue:

4. Layer shift / bad surface taller objects

I bought this printer mainly to print 500mm tall objects in a race car project I'm involved in, I've done some tests with the standing minigroot model and some other models, and at around 430-450 mm Z height I always get a massive layer shift. It looks like the nozzle crashes into the print because of lacking Vertical Lift. And the print moves/vibrates as well from the Y axis movements. Is it recommended to turn down the acceleration for the Y axis to get a more smooth movement? Thats the only thing I can think about, I'm NOT printing fast.. the last fail I turned the speed down to about 20mm/s just to be sure, took like 10 hours to finish 20cm of the model before it failed. If I dont get layer shifts, I get some heavy lines on the outside, like the outer outline misses the line pretty much (se photos).

IMG_1567.JPG


IMG_1565.JPG


UPDATE: Just checked my extruder, and it extruded 93mm when I sent the command to extrude 100mm, so I'm under extruding according to that, which is the opposite of what I was hoping for :) Old steps 96, so my new steps is 102.7, trying to update it through OctoPrint terminal but it doesn't bite...Where do I find the configuration.h file?

UPDATE 2: Trying to print a 350mm x 20mm x10 mm long part now, tried to both print it on the left side of the bed along the Y axis and on the front side of the bed along X axis, but I have to adjust Babystep Z in a way that the one side is almost skipping since the nozzle is too close, to get the other side ok. And even then it warps...
My front left corner is aparently lower / leaning down. Shouldnt the Probing deal with that?
These users thanked the author oneaday for the post (total 0):
User avatar
oneaday
 
Posts: 46
Joined: Tue Dec 27, 2016 6:41 am
Has thanked: 3 times
Been thanked: 2 times

Re: Fine-tuning & Increasing Performance of your gMax Printe

Postby PianoPrint » Thu Feb 02, 2017 1:16 pm

OK. So I read all your post. There are a lot of things going on here and it will take some time to address them all. With that said I had the same issues for some time until I systematically eliminated them all. The gMax printer is a good printer, but you need to understand it in depth where the machine is, what it can offer and how to get there.

In general as configured by gCreate the machine is meant to print big, slightly rough and bulky, as its size dictates that. However, with some fine tuning you can get small and detailed. I have two other printers I put together that were mainly for smaller detailed work, but now I exclusively use the Gmax as it produces perfect prints.

If you have the patience I am confident that we can solve all your printing issues.

Do me a favor though, on the fist page of this thread tell me what have you already done so far from the long list of impovements?

Have you done the:

5. Calibrating Filament Extrusion Multiplier - Calculating the Setting

I would start from there. If you are not familiar with the process I can a share the information.

Also, I would like to understand your printer baseline as far as what equipment you have. Do you have the new upgraded bed with the heated pad and borosilicate glass? Or are you using the acrylic bed with buildtack on top?

What hotend do you have? I have used both the Jhead, and now the E3D V6 in 4.5mm. Let's start form there first.

Also, I do not use any more the BabyZ as I think it is a waste of time once you level mechanically your bed and set the Z height thorough Marlin and adjust with the Bltouch sensor height adjustment screw. The rest is handled by Marlin and the Bltouch sensor.

I typically print in 0.20mm layer height. If I change to different layer heights I do not mess any more with the baby z or the Bltouch height screw. The only thing I change is the % height for the first layer. I use S3D as a slicer.

Typical setting for first layer height for 0.20mm:

First layer speed 25%
Bed temperature 78C for PETG, and 60 for PLA
First layer height 138%
Fist layer width 100%

On the "Other" tab, in S3D, the general printing speed is set between 30 to 45 mm/s. I like to print around 35mm/s, outside layers to 65% and inner layers to 75. X/Y movement set to 50mm/s, and z to 100%.

Sure the prints take a little more time, but the results are flawless.

What also helped the gMax printer bed quite a bit, as the glass and silicone heated mat are heavy and tend to sag in the middle, was to add an adjustable leveling screw in the middle of the print bed. The bed is big and in need to stabilize it in the middle, thus the leveling screw. I'm not sure why gCreate has not implemented something like this yet, but I'm sure they are thinking about it. Any way, it took a little of drilling and taping, but once you set it you pretty much forget it. Now the bed flatness is leveled to 0.008" (0.20mm), and I did that with a filler gauge. Now by setting the first layer height slightly above that, say 140% of 0.20mm takes care of any variation or what is left over from the bed flatness. Now I never have any first layer issues. The fist layer is flat, consistent and crisp. I just push print and walk away.

Below you can see a picture of the middle of the bed leveling spring screw. It has helped tremendously.

Best,

Eric
These users thanked the author PianoPrint for the post (total 0):
Attachments
2.jpg
2.jpg (17.83 KiB) Viewed 1819 times
1.jpg
PianoPrint
 
Posts: 45
Joined: Tue Aug 04, 2015 2:37 pm
Has thanked: 0 time
Been thanked: 17 times

Re: Fine-tuning & Increasing Performance of your gMax Printe

Postby PianoPrint » Thu Feb 02, 2017 3:30 pm

Here is another example of the quality of the prints.
These users thanked the author PianoPrint for the post (total 0):
Attachments
20170115_213901.jpg
20170118_191157.jpg
PianoPrint
 
Posts: 45
Joined: Tue Aug 04, 2015 2:37 pm
Has thanked: 0 time
Been thanked: 17 times

Re: Fine-tuning & Increasing Performance of your gMax Printe

Postby oneaday » Mon Feb 06, 2017 5:37 pm

Thank you for your answer!

Looking at your tall print there at the end tells me that I'm pretty ok with surface finish. I'm just used to a baby skin like surface up to 200mm prints on the Prusa's I have.

To answer your questions:

Yes I've calibrated my extruder and I've updated the E Steps / mm through the LCD (havnt had time to dig into how I write it permanently, will do that later when I find some time.

I have one e3D hotend, and I've just installed an e3D hardened 0.8mm nozzle, trying to tune in the settings atm.
I'm in direct contact with Kyle as well, I've been running some tests for him, we'll see what he thinks, but its pretty clear that my bed is a bit higher on the right side than on the left side.

After I installed the new nozzle, I did auto home, I used a very thin paper and lowered the nozzle to Z 0.0, it was a bit high, so I turned both screws on the BLTouch one quarter of a turn and did auto home again, this time it just touched the bed when I lowered the Nozzle to Z 0.0.

I have a heated glass bed with Buildtak on that, which I'll replace with PEI in a week or two. Not a big fan of the buildtak, personal preferences probably though, and since I've been using PEI on the Prusas for a long time I know all the tricks to increase (and decrease) adhesion for certain filaments.

Printing the 0.6mm layerheight model now with my own set up profile, will try the one gCreate offers from here next test, because this works pretty bad :) I'm having feeding issues since it cant reach my set temperature when the partcooling fan is turned on more than about 70%, when the fan is on with full speed it cant reach a temp above 205 degrees C, when I turn it off it reaches 235 degrees in like 10 seconds. I've now set my nozzle to 255, and raising the fan 10% at a time. When I reach 80% cooling the temp drops, at 70% fan it stays at 246 degrees, but cant reach 255 again.

And it seems like Im stuck at about 30mm/s if I dont want Extruder skipping.
These users thanked the author oneaday for the post (total 0):
User avatar
oneaday
 
Posts: 46
Joined: Tue Dec 27, 2016 6:41 am
Has thanked: 3 times
Been thanked: 2 times

Re: Fine-tuning & Increasing Performance of your gMax Printe

Postby PianoPrint » Tue Feb 07, 2017 2:53 pm

Some more examples of prints and first layer print quality. The RC printed plane has a 60cm wingspan. The layer is rather course at 0.20mm layer height. Since my nozzle is 0.4 in diameter it will print best in increments of the nozzle diameter. For example the layer height should be in multiples of 0.04, 0.08, 0.12, 0.16, 0.20, 0.24. I could have printed in twice as good as a resolution as what is shown for instance 0.12mm. But there is no value for me due to the time involved to printing the items.

In your case, with a 0.8mm nozzle I would limit your layer height to the following 0.16, 0.24, 0.32, 0.4mm. Anything more than that it would be difficult for the extrude to push the filament fast enough (most likely will be skipping steps if you do not extrude less than 30mm/s). The 0.8mm thick nozzle is made for quick non detailed work. The corners of parts will not be sharp and details will be get lost in the thickness of the extrusion. To expect good detail and surface finish out a 0.8mm nozzle would be unreasonable due to its physical limitations.

On the E3d V6 are you using the blue silicone hot end boot? It insulates the head and create a stable temperature. Did the E3D V6 come with the printer or did you installed it later? It could need a PID auto-tune for the temperature in order to get calibrated. I had to do mine ( I did not buy the printer with the E3d, but installed it later).

What material are you printing that you need to run 255 C? For PLA I run 208 C with 70% fan, for ABS 240 C with 0% fan, and PETG 241 C with 70% fan. On all filaments when bridging I use 95% fan for that layer.

The aluminum print bed it could have been hit during transport. I had a small issue with mine. Place a straight edge on top of each side of the aluminum bed (after removing the glass and heated silicone mat from it) and bend slightly as needed in the opposite direction of the bend to straighten it. Then do a mechanical bed leveling with a filler gauge and the nozzle on top of each bed corner (fully assembled with the glass and silicone mat). That is all you have to do for the bed. Then set the height with your Bltouch and you should be fine.

As far as the extruder skipping that is a function of the nozzle being too wide in diameter (0.8mm), the heat extrusion temperature, the filament extrusion rate (expected print speed), and the appropriate voltage setting on your extruder stepper motor driver that is plugged on top of the RAMPS board. You can adjust all of the above to obtain favorable results. Are you familiar how to increase the voltage input by turning the pot screw of the stepper drive? Keep on increasing in 5 degree increments while printing until it stops to click.
These users thanked the author PianoPrint for the post (total 0):
Attachments
20170206_173221.jpg
20170206_225054.jpg
20170206_224546.jpg
PianoPrint
 
Posts: 45
Joined: Tue Aug 04, 2015 2:37 pm
Has thanked: 0 time
Been thanked: 17 times

Re: Fine-tuning & Increasing Performance of your gMax Printe

Postby oneaday » Thu Feb 09, 2017 5:34 am

Hi!

Yes im aware of the "issues" with a larger nozzle, but I'll be printing alot of models where the surface finish is not of priority, layer bonding is more important.

I'm printing alot of Colorfabb NGEN, its recommended to print between 220-240, but to get a good flow without any skipping I had to turn the temp up to 250-255 as well as lowering the speed to around 20-30mm/s

The printer came with the E3D hotend, I havnt done anything with it hardware wise yet. (except the nozzle switch)
My E3D hot end did not arrive with the silicon sock, although I have a few laying around, I will mount it and see.

When I print at 20-30mm/s with NGEN and 0.6 layers I cant increase the fan more than to around 30-40% before the temp starting to drop.

I'll soon replace my buildtak with PEI, ill take a look at the aluminium bed then.

I tried to mount the soc but it cant grab the heatblock, I had to modify it a bit, hopefully it will stay.. we'll see.
These users thanked the author oneaday for the post (total 0):
User avatar
oneaday
 
Posts: 46
Joined: Tue Dec 27, 2016 6:41 am
Has thanked: 3 times
Been thanked: 2 times

Re: Fine-tuning & Increasing Performance of your gMax Printe

Postby oneaday » Thu Feb 09, 2017 7:59 am

I have another question for you, printing a 500mm tall model now.

I have some skipping happening but at the exact same two positions during the layers each time, and it has no effect if i print at 220 or 270 degrees, nor if I print at 20mm/s or 50mm/s.

Any ideas regarding that?
These users thanked the author oneaday for the post (total 0):
User avatar
oneaday
 
Posts: 46
Joined: Tue Dec 27, 2016 6:41 am
Has thanked: 3 times
Been thanked: 2 times

PreviousNext

Return to Community Troubleshooting Forum

Who is online

Users browsing this forum: No registered users and 1 guest