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Hi everyone. Merry Christmas and Happy Holidays!
I’m new here and just got my Robox…9 days running. I’m from California as you can tell from the topic title. So far very happy with it…big fan. I have an AutoMaker question. Does anyone know how to change AutoMaker’s default units of measure from mm to inches?
I’m using SketchUp Make to create models but I notice that if I use “inches” in SketchUp, the model I import in AutoMaker has to be scaled to approximately ~2540% (1in=25.4mm) to get it to the actual size intended. If I use “mm” as the units of measure in SketchUp and export to .stl or .obj, I have no problems importing to AutoMaker and is scaled correctly in the model viewer at 100%. I’ve seen forum members mention inch units in postings so there’s probably a way to do it.
I have either exporting in mm or scaling 2540% as a workaround, but just wanted to test whether changing the units in AutoMaker itself fixes the import of .stl or .obj that has inches as units of measure. I don’t know if this a problem in the file format or in AutoMaker. If AutoMaker, I’ll gladly file a support ticket. Either case, I think AutoMaker should handle units of measure conversions automatically.
I attached the test models (24,5mm x 24.5mm x 6.35mm with a 12.7mm bore) I’m using to test accuracy and calibration.
Other Notes: PLA Draft Print is accurate only on the first few layers of the print with a width of ~25.4mm. Up to ~3% Warping and shrinking on the width on subsequent layers as expected I think. The 12.7mm bore has shrunk by about ~7%. Printing at 107% the bore is a perfect fit for 0.5in or 12.7mm aluminum tubings, but the outer width increased by 4-6% . Hoping to get Cura slicer for Christmas or soon to test how much better slices are with AutoMaker 1.01.
- This topic was modified 6 days ago by robyneil.
Manifesting ideas is still difficult, but at least we're one step closer...In reply to: covering the field
@jabberwocky A waterjet or laser should be pretty easy to use to cut the Geckotec. It is just the cost of the setup that is going to be prohibitive. Waterjet in my area starts at about 100.00.
If you have access to a dial indicator, I can send you an STL file for a mount that will let you probe your bed and see how far it is out of flat. The bed on my Beta unit is within .007 inches of flat, which is within tolerance. My new production printer is .020 inches high to low and that is pushing things. I think I will be requesting a new bed.
I found that the first set of PEI sheets that came with my Beta printer were not very consistent in thickness nor in size. I have since received new sheets in the Beta update box that greatly improved the quality of the PEI sheet and made a huge difference. They are slightly larger and make a tighter fit in the bed. They are hard to install correctly, but they don’t bow and they stay put. I am guessing that much of your uneven bed may be due to the PEI sheet not fitting right and less with actual bed unevenness. The Beta beds were all machined and hand-finished, so they should be pretty flat. The new ones are bead-blasted and they aren’t as even.
In reply to: covering the field
I have three Robox units now and a CobbleBot coming in a couple of months. The reasons I have mor ethan one:
1. Multiple simultaneous prints. The Robox allows you to start one print and unplug the printer. You can then move on to another printer and start another print. It also allows faster turn-around in production parts.
2. Versatility - I can run prints with different materials without having to change filament. I use some exotic filaments like BronzeFill and when your filament is over 100.00 USD per pound, it makes sense not to change the filament unless you have to.
3. The Robox is great for smaller pieces. I have ordered the CobbleBot because it allows parts up to 15 inches on a side to be printed or will allow a large number of smaller parts to be printed at the same time.
4. Cost - The printer and material cost for FDM printers like Robox is considerably smaller than SLS or lithography printers. While there are some disadvantages, I find that they can be overcome with intelligent design and material choice.
In reply to: Print Challenge
I have found that increasing through-hole sizes in ABS and PLA by .025 inches tends to give more accurate through-hole results.
In reply to: Brim Perimeters - Is it cheating?
@davidmason83 Do a nozzle height calibration. This sets your base nozzle offset. Then with the PEI bed in place, run a print, I use the pyramid, and cancel it after the first layer is done. Peel off the first layer and measure thickness with calipers. Use the option in the nozzle calibration screen to adjust the nozzle offsets, both at the same time, until the first layer is the thickness you want it. Mine tend to run between .010 inches and .015 inches. This gives space for the PEI to be a little uneven and makes sure the first layer sticks well.
It takes trial and error. The only machines that print perfectly out of the box are the tiny ones because they don’t have large beds and they can be stiffer. Even those machines take some learning and trial to get everything set just right for perfect prints every time.
In reply to: Brim Perimeters - Is it cheating?
@BHudson, Thank you for that. I will look at putting your advice into practice. Could you give a bit more info on running the nozzle .015 inches away from the bed?
Many thanks!
In reply to: Brim Perimeters - Is it cheating?
@davidmason83 I do small parts all the time. I have completed parts that are less than an inch long and a quarter inch wide. I printed a clip yesterday that is four paths thick and complex shaped. It turned out almost perfect, didn’t come off the bed, and required very little trimming. I have printed complex parts in that size that require support in order to print properly.
The results you get depend greatly on the material you choose, how you build your model, and how you prep your bed. Slic3r adds the remainder of the variables.
PLA doesn’t work well for small parts because it doesn’t cool and harden fast enough. Nylon works better but warps quite a bit. Polyester materials such as ColorFabb _XT and Taulman T-Glase work extremely well for small parts. BronzeFill from ColorFabb also works well for small parts, but needs more cleanup and dimensional adjustment.
The keys I have found to good bed adhesion are to clean the bed with IPA and a microfiber cloth after every print and to run the nozzle about .015 inches from the top of the PEI. This forces the material against the bed and makes it squish out to the sides to get a solid first layer. By doing those steps, I have very few parts that ever come off the bed and those are usually when the bottom of the part is much smaller than the top and the weight of the part pulls it off the bed. The other reason some parts come off is that the material warps and the nozzles hit the printed part and knock it off.
In reply to: Warped PEI bed
@jamie I have heard from CEL that there are some beds that were made wrong; the aluminum for the heater base is out of spec. This is mostly around the edges. One of the reasons to use the PEI is because it tends to level out those issues. If you have access to a dial indicator instrument, you can print a mount that will allow you to probe your bed and see if it is out of spec. Mine is out .007 inches max. It makes a difference in printing, but CEL says that it is in spec.
Dial Indicator mount STL attached.
If you suspect the gantry is the issue, run the gantry and Y level sequences in the Advanced tab under Maintenance. If you watch the Z screws, you can see them turn as the system adjusts for the bed profile. Run the Gantry level two or three times. It should adjust for the first two and not for the third. Do the same with the Y level. Once the system stops adjusting, you will be at the best setting and that will be saved. Your Robox will also adjust that every time you print.
There is a new bed level system being planned in the software that will expand the capability of the Robox to deal with unlevel beds. CEL is very excited about adding that capability to the system, but it will be a while before it is released.
@bhudson “Try setting your nozzle a little closer to the bed. I have mine between .010 and .020 inches from the surface of the bed. The material is pressed flat between the nozzle and the bed. “
That is exactly what I did.
@weechan Try setting your nozzle a little closer to the bed. I have mine between .010 and .020 inches from the surface of the bed. The material is pressed flat between the nozzle and the bed. It causes a little buildup on the nozzle for the first layer but I have few problems with parts sticking. The only ones I have had come loose are long prints with PLA or prints with tiny bases. I have switched to using T-Glase and ColorFabb _XT for all my prints that matter and have had great luck - the _XT does not come off the bed, sometimes it sticks even when the bed is cool. It is much less sensitive to the bed being clean, also.
4.93 cm3 - 1.08 inches x .9 inches x 1.71 inches
Sorry day 2 ever on a message board!
Topic: Action man
A new work-in-progress project of an articulated action man (for eventual stop motion animation). There are twenty-nine files but containing a lot more pieces. This is the head which I had tried to print with the neck sections at the same session, but after a successful start the neck sections slid off and I had to restart. That’s not exactly a problem since the time required for printing several sections in one go really takes too long for one session - I have to let it run overnight. The guy who designed this figure is a professional model-maker and has produced the files so that they all start with a flat side. Thus support struts are not needed, each part is in two sections that you stick together afterwards. When fully assembled the figure will be 18 inches tall and have 70 individual articulated joints.
