Show all posts by user
People building or using RepRaps.
Re: Titan Aero E3D V6 mount and duct for Core XY - 5 months ago
Why not just mount the fans down where the duct ends and do away with the duct entirely?by the_digital_dentist - CoreXY Machines
Re: A new design - CoreXrY - 5 months ago
What is the point of adding extra motors, unless you want to use motors that are insufficient to move the mechanism by themselves? And why would you want to do that?by the_digital_dentist - CoreXY Machines
Re: Titan Aero E3D V6 mount and duct for Core XY - 5 months ago
Axial fans with ducts for print cooling? Does it work? You really should try a radial fan. They tend to work better with ducts. In this blog post there are a couple videos of a simple duct mounted on an axial fan: The duct causes pressure build up behind the fan and the result is very little air flow out of the duct (at the intended place, anyway). I have an old CubeX printer that used axialby the_digital_dentist - CoreXY Machines
Re: A new design - CoreXrY - 5 months ago
Interesting. It doesn't look like the overall belt length is any shorter (might actually be a little longer), but you have 3 shorter belts instead of 2 long belts. It might be a good way to build a large corexy printer.by the_digital_dentist - CoreXY Machines
Re: Building a CoreXY : machined or printed parts ? - 5 months ago
Regarding Z axis resolution, you want full step resolution to be a "nice" number that is probably smaller that any layer thickness you'll ever print. For example, in my printer's Z axis I selected the pulleys to work with the motor's 200 steps/rev and the 30:1 reduction to yield 20 um per full step. When you print you want to print in multiples of the full step resolution to minimize Z axis artifby the_digital_dentist - Mechanics
Re: Building a CoreXY : machined or printed parts ? - 5 months ago
I like belts for the Z axis. Probably about the same cost as lead screws by the time you add in either a brake or worm gear drive for the motor. Belts can't cause any wobbly artifacts in the prints, and you can use arbitrary lengths, as long as you like, which is nice for large/tall printers.by the_digital_dentist - Mechanics
Re: Building a CoreXY : machined or printed parts ? - 5 months ago
Z hop isn't very useful with stringy materials like PETG. It's great with ABS and PLA. IRIC, I shut it off for PETG and TPU. Ball screws tend to cost more than lead screws, and the pitch tends to be much larger, so you give up some Z axis resolution unless you use pulleys to reduce the Z axis drive with them.by the_digital_dentist - Mechanics
Re: Building a CoreXY : machined or printed parts ? - 5 months ago
Yikes! That's one I haven't heard before! Yes, your common sense is correct- machined metal parts are superior to the same parts printed from plastic.by the_digital_dentist - Mechanics
Re: How reduce noise from this printer? - 5 months ago
Ooh! That's an old-school printer! I couldn't hear any audio on that video (my work computer isn't well provisioned). It looks very much like the X axis isn't square with the Z axis. That was a common problem in that type of machine because it has two Z axis motors. That was why people came up with auto tramming/leveling (instead of fixing the cause of the problem). The steppers jump every timeby the_digital_dentist - Printing
Re: Tall 3D printers under 5000$/€ - 6 months ago
If you have any interest and access to some basic tools you could build your own printer to meet your own specs. If you don't want such a big project, you could buy a machine that has adequate XY range, controller, etc., and then just extend the Z axis to whatever length you need. As a point of reference, I built UMMD for about $1200 all-in, IRIC, but I shopped carefully including getting t-sloby the_digital_dentist - General
Re: Heated chamber : heater placement - 6 months ago
I made that vase print (a bread box) about 8 or 9 months ago, I think...by the_digital_dentist - General
Re: Heated chamber : heater placement - 6 months ago
Horizontally striped transparent PETG print- low print speed (15 mm/sec?) in frosted sections, faster (30 mm/sec?) in clear sections: The filament is "edge glow glass" PETG from Keene Village Plastics. I buy the stuff in 5 lb spools.by the_digital_dentist - General
Re: Heated chamber : heater placement - 6 months ago
I have found that if the PETG sits in the heater block too long it gets bubbly and prints "frosted". I have taken advantage of it by printing objects with horizontal stripes by speeding up and slowing down the print at 10 mm Z intervals. The result is a single walled vase that has alternating bands of clear/shiny and frosted appearance. I'll post a picture when I get a chance. I haven't tried prby the_digital_dentist - General
Re: Heated chamber : heater placement - 6 months ago
I often print PETG at 240C with a 1 mm nozzle, typically 1.2 mm line width, 0.5 mm layers, at 30 mm/sec (18 mm^3/sec) on 70C bed. No issues with first layer sticking. No chamber heat- just room temp.by the_digital_dentist - General
Re: Heated chamber : heater placement - 6 months ago
The single motor Z axis is such a simple thing but there's a lot of resistance to doing it, probably because everyone has seen cool youtube videos of machines autoleveling a bed that starts 45 degrees away from level. I think it's better to keep the system trammed than to let it get out and bring it back. A warp detector is sort of like a filament run-out detector. It's best not to let it happenby the_digital_dentist - General
Re: Heated chamber : heater placement - 6 months ago
I've seen a couple guys building high temperature printers over at the Duet forums. They are building them to print materials like PEEK, etc. That's a completely different build (an oven) compared to just getting things warm enough to print ABS. My printer has a chamber volume of about 420 liters IRIC, and a 500W heater. It takes about 20 minutes for the chamber temperature to reach 50C, so I usby the_digital_dentist - General
Re: Heated chamber : heater placement - 6 months ago
You need the chamber to get up to about 50C (or higher) to prevent layer splitting and warping, but you don't want a lot of air movement as it will cause splitting and warping in spite of the temperature. If you use a PTC heater that limits its own temperature to a safe value, you can put it almost anywhere, but under the bed is probably the best place to keep it out of the way. Make sure there iby the_digital_dentist - General
Re: Do all metal hotends only work well on direct drive? - 6 months ago
Retraction is typically very short for direct drive extruders, usually under 1 mm. Longer retractions will pull hot filament into the throat of the heat break and cause jamming, as you have found out. You can print with flexible filament with a direct drive extruder, something you can't do with a Bowden extruder. However, direct drive extruders can create a specific type of print defect that isnby the_digital_dentist - Tech-Talk
Re: Reliable core XY printer - 7 months ago
I usually end up having to repair something on my printer about once every 2 years. In particular, the adhesive that holds the heater and PEI to the bed plate is good for about 2 years, then lets go. I solved the heater problem by using high temperature silicone to attach it to the bed plate, about 3 years ago, IRIC. I noticed that the PEI is starting to lift at one corner again- it's been a coupby the_digital_dentist - CoreXY Machines
Re: Reliable core XY printer - 7 months ago
My printer has been very reliable. I designed it so I didn't have to use any autoleveling. I level the bed once and don't have to touch it again unless I modify the Z axis. I never have problems with the electronics or the belts. I used an absolute minimum of plastic parts in the printer, and used quality Japanese made linear guides purchased used via ebay for about the same price as the crappy Hby the_digital_dentist - CoreXY Machines
Re: Belt driven Z axis - 7 months ago
My corexy machine, UMMD, uses a belt lifted Z axis. It has a NEMA-23 motor with a 30:1 worm gear reducer and it works perfectly. A full step of the motor moves the 3.5 kg bed 20 um. The bed doesn't move when the power is cut (thanks to the worm gearbox), so it is possible to resume prints. I have stacked 4 kg on the bed to do the belt stretch testing and it had no problem lifting it, even thoughby the_digital_dentist - Mechanics
Re: Test Rods and Bearings? - 7 months ago
Take the belts off, move the linear bits around by hand. If they move smoothly and quietly, and don't wobble, they're fine.by the_digital_dentist - Mechanics
Re: A new, smaller sand table mechanism: Arrakis - 7 months ago
I haven't shot any new videos since redesigning the sandbox, but the mechanism hasn't changed, so all the videos in this playlist will give you an idea what it is like, including the noise level when it runs. Arrakis playlist I'll shoot more video in different colors soon and add them to the playlist. I've noticed that after about a year of relatively heavy use, some of the pulley bearings areby the_digital_dentist - CoreXY Machines
Re: A new, smaller sand table mechanism: Arrakis - 7 months ago
At Milwaukee MakerFaire 2022: Unfortunately, there was an overhead light shining directly down on the table which wasn't optimal for the effectiveness of the two color lighting. The machine worked flawlessly on both days except that on Sunday, for some reason, 3 people found the foot switch and killed power to the table. I should have put a box over the switch...by the_digital_dentist - CoreXY Machines
Re: A new, smaller sand table mechanism: Arrakis - 7 months ago
I only tested the glass beads and baking soda, so don't know about others, but the motion through the glass beads is very rough and it makes quite a bit of grinding noise, and the baking soda is much smoother and quieter. I see a lot of people using different kinds of actual sand for their tables and wonder if they've tried baking soda, because it is probably much smoother due to the finer particby the_digital_dentist - CoreXY Machines
Re: A new, smaller sand table mechanism: Arrakis - 7 months ago
I tried glass spheres- some of the type to make reflective striping on roadways. Not so good. They were very coarse, and though you might expect them to be very reflective, they are retroreflective- they return light back to its source, not to your eyes which are at a much higher angle than the lights that illuminate the table. Lighting from under the table isn't great either- the patterns are eby the_digital_dentist - CoreXY Machines
Re: A new, smaller sand table mechanism: Arrakis - 7 months ago
Arrakis 2.0 will make its public debut at the Milwaukee MakerFaire this weekend. I have redesigned the sandbox, switched to RGB LEDs, and will soon be simplifying the electronics a bit. The old sandbox had a 1/4" plywood bottom covered with a sheet of EPDM rubber. There was an air gap between the magnet and the bottom of the sandbox to help keep noise down. I found that the bottom of the box woby the_digital_dentist - CoreXY Machines
Re: Life span of plastic parts? - 8 months ago
You can buy metal mounts from China for $42 each (incl shipping to US), hogged out of a solid billet of aluminum (overkill, I'd say, but pretty)- you still have to add mounting holes or tap the holes for mounting the motor on the mount: My tube based mounts are a lot cheaper to make if you have a drill press.by the_digital_dentist - CoreXY Machines
Re: Life span of plastic parts? - 8 months ago
No, didn't follow existing design. I did that 4 or 5 years ago, and haven't seen it used by anyone else. Click the link on Ultra MegaMax Dominator in my sig, below to see more of it.by the_digital_dentist - CoreXY Machines
Re: Life span of plastic parts? - 8 months ago
I made motor mounts out of rectangular aluminum tubing- very cheap, and easy DIY, even with limited tools. They don't flex under belt tension, transfer heat away from motors (though in my printer, they may actually be transferring heat to the motor when the chamber heater is in use), and automatically provide an accurate, square mount. You can attach them to the printer's frame with screws in theby the_digital_dentist - CoreXY Machines