RE: The Core One Kit Waiting List
(When did "self tapping machine screw thread in plastic" become an accepted design practice, by the way? It's bad enough to see self-cutting screws with coarser threads in cheap plastic products. But those at least get some grip in the plastic. I did not expect to find those M3 threads in a Prusa design; always felt it was a hobbyist's kludge. Well, at least they made sure to only use them for screws which are not expected to be loosened and reassembled later.)
M3 threads self tapped into plastic works fine. The thread pitch is small and the difference between the major and minor diameter is only .5mm. So you can fairly easily use the screw to create the threads. As a bonus it also acts kind of like a Nylok screw in the sense that they won't fall out easy. There are plenty of you tube videos out there testing the strength of threads created this way and it's really good.
The only reason you might not want to use threads like this is if it's something that will be frequently taken apart. A threaded insert works better in those situations, but those have their own issues as well. Mainly having to do with the install, especially if the position is critical.
On larger threads it's a different story.
RE: The Core One Kit Waiting List
For @jurgen-7:
Yes, threads can also be made during the production of parts, there are even tools that make threads even when pressing parts and bend the part into the correct shape, I myself worked in a company that makes it like this, but the tool for that is so expensive that it would not be worth it here. But if you made the threads on a CNC (which is certainly possible), you would still have to clean them one by one after painting, which is basically the same operation as cutting the threads as new and thus you would actually have two operations to produce the same thread. Or not clean it and state in the assembly instructions that the threads must first be "stretched" with a screw. And as for that guy, you would be surprised how many different such operations are done manually piece by piece in professional production. Not everything is worth some automation and robotics.
RE: The Core One Kit Waiting List
Just a thought regarding the untapped holes some have found:
Is there a chance Prusa were made aware of this issue and halted the kits shippping for a couple of days while the issue was rectified?
A few of us pointed out that after a flurry of activity on the 31st of March, seemingly very few (if any) kits shipped on the 1st/2nd April.
am I right in saying the few people with the issue all had their order shipped on the 31st March ?
RE:
Just a thought regarding the untapped holes some have found:
Is there a chance Prusa were made aware of this issue and halted the kits shippping for a couple of days while the issue was rectified?
A few of us pointed out that after a flurry of activity on the 31st of March, seemingly very few (if any) kits shipped on the 1st/2nd April.
am I right in saying the few people with the issue all had their order shipped on the 31st March ?
No. MarcG, who reported the missing threads today, had his order shipped on April 3rd.
You are giving too much credit to Prusa. They are not that fast in responding to anything. 🙄
RE: The Core One Kit Waiting List
A mistake creeps in, it happens. Let's not make a tragedy out of it.
RE:
Sorry I re-read the thread Jurgen, your part was fine.
so it’s just one instance of the holes not being correctly threaded, and one broken fan thingy ?
RE: The Core One Kit Waiting List
I ordered Feb 2nd and I too don't have a batch number...just TBA. I contacted support and they said mine would probably ship out mid May. Didn't give me a batch number or anything just said mid may.
I ordered 3rd Feb, I'm batch 5, expected 14th May, but I do still have the filtration in my order, which is holding it back. So i would expect you to be in front of me in the 'queue'.
You got any other items in your basket that could potentially delay it? Buddy Cam and Filtration are the 2 main ones, unless you've ordered some filament that isn't going to be available until next Jelember?
Scott
I ordered 8th Feb, also in batch 5, expected shipping starts 14th May.
I originally had the filtration system and the camera in the order but cancelled them a few weeks ago as I thought it would hold up the order even more.
RE: The Core One Kit Waiting List
Sorry I re-read the thread Jurgen, your part was fine.
so it’s just one instance of the holes not being correctly threaded, and one broken fan thingy ?
A couple more teething issues -- some of the holes for self-tapping screws being too loose, some overly tight (manufacturing tolerances?), rubber feet having a tendency to come away from their adhesive (late design change, not properly evaluated).
My general impressions from the build were a bit mixed regarding the level of care that was taken:
I quite liked the packaging and the instructions (except for a few small oversights which are already being fixed). I was really impressed by the accuracy of the frame profiles -- just screw them together and you have a perfectly squared frame. I was really disappointed by the wobbly acrylic panels, including the door and lid -- would have been so easy to make them all a millimeter thicker. The fiber-reinforced printed parts look really good and high quality; the glossy black parts (PETG?) look crude and cheap in comparison, also regarding print quality -- I wish they would move away from them.
I was profoundly irritated that there were no checks at all to make sure over-constrained parts actually fit together: Two smooth rods and three lead screws in Z are just bolted to the base and to the heatbed with no chance in hell that all their lateral positions will align. Two smooth rods in Y are bolted onto the CoreXY frame and are never checked or adjusted to be parallel. That really makes me wonder who was careless here: The design engineers? The assembly technicians? The instruction writers? All of them?
So, a mixed bag. Mostly things that can be fixed with careful assembly and some extra tools, except for the wobbly acrylic.
RE: The Core One Kit Waiting List
Yesss, i got an update(few days ago)
My Prusa Core One Kit + cam order date is 19-2-2025 (Netherlands) and shipping starts: 30 may (Batch 8)
RE:
Sorry I re-read the thread Jurgen, your part was fine.
so it’s just one instance of the holes not being correctly threaded, and one broken fan thingy ?
A couple more teething issues -- some of the holes for self-tapping screws being too loose, some overly tight (manufacturing tolerances?), rubber feet having a tendency to come away from their adhesive (late design change, not properly evaluated).
My general impressions from the build were a bit mixed regarding the level of care that was taken:
I quite liked the packaging and the instructions (except for a few small oversights which are already being fixed). I was really impressed by the accuracy of the frame profiles -- just screw them together and you have a perfectly squared frame. I was really disappointed by the wobbly acrylic panels, including the door and lid -- would have been so easy to make them all a millimeter thicker. The fiber-reinforced printed parts look really good and high quality; the glossy black parts (PETG?) look crude and cheap in comparison, also regarding print quality -- I wish they would move away from them.
I was profoundly irritated that there were no checks at all to make sure over-constrained parts actually fit together: Two smooth rods and three lead screws in Z are just bolted to the base and to the heatbed with no chance in hell that all their lateral positions will align. Two smooth rods in Y are bolted onto the CoreXY frame and are never checked or adjusted to be parallel. That really makes me wonder who was careless here: The design engineers? The assembly technicians? The instruction writers? All of them?
So, a mixed bag. Mostly things that can be fixed with careful assembly and some extra tools, except for the wobbly acrylic.
I’ll be keeping an eye out for the things you’ve mentioned when my kit arrives, hopefully Thursday.
I fully agree with the PETG comment, it’s a great filament but just generally looks awful.
I only ever use PETG for functional parts that I’ll never have to look at…with the capabilities of the Core One I’ll hopefully be reprinting the PETG parts with something sexier if/when the parts are made public.
RE: The Core One Kit Waiting List
The fiber-reinforced printed parts look really good and high quality; the glossy black parts (PETG?) look crude and cheap in comparison, also regarding print quality -- I wish they would move away from them.
I don't know which parts are made of PETG, but sometimes it's the better material.
I printed the parts for my MK4S and MMU3 in PCCF.
For some parts that require some flexibility, PCCF is just too stiff and more likely to break.
RE: The Core One Kit Waiting List
I don't know which parts are made of PETG, but sometimes it's the better material.
I printed the parts for my MK4S and MMU3 in PCCF.
For some parts that require some flexibility, PCCF is just too stiff and more likely to break.
I would say they have used PETG mainly (exclusively?) for cost reasons. E.g. for the side filament sensor and for various covers in the back. They have certainly used PCCF where it had technical advantages, and they have even used it for some cosmetic parts, presumably just because it looks better -- e.g. the Nextruder side covers.
So they have certainly chosen the materials deliberately and for plausible reasons: If a part is hidden on the inside or in the back of the printer, and does not need the stability, let's save a few pennies. But this does not work so well in a kit, where the customer handles every part and wants to feel like "this is a beautiful machine inside and out".
RE: The Core One Kit Waiting List
I ordered Feb 2nd and I too don't have a batch number...just TBA. I contacted support and they said mine would probably ship out mid May. Didn't give me a batch number or anything just said mid may.
I ordered 3rd Feb, I'm batch 5, expected 14th May, but I do still have the filtration in my order, which is holding it back. So i would expect you to be in front of me in the 'queue'.
You got any other items in your basket that could potentially delay it? Buddy Cam and Filtration are the 2 main ones, unless you've ordered some filament that isn't going to be available until next Jelember?
Scott
I ordered 8th Feb, also in batch 5, expected shipping starts 14th May.
I originally had the filtration system and the camera in the order but cancelled them a few weeks ago as I thought it would hold up the order even more.
So removing the filtration from your order didn't change your expected delivery? Interesting 🤔 I may just leave my order be and see what happens, although I'd like to have my printer yesterday, it'd be nice to not have to pay for 2 separate orders, especially when I know I'll need it further down the line to print ABS etc.
Scott
RE: The Core One Kit Waiting List
Got to admit, packaging and design issues like this are starting to make me a bit twitchy about the whole thing. For the price-point, I'd expect better.
The missing threads in the bracket are not a design issue, but a manufacturing problem. My brackets were made correctly. But strange how that kind of problem could have crept in; I would very much assume that all those threads are cut via CNC in one go?
I felt like a lot of thought had gone into the packaging -- not only custom cardboard and foam inserts to hold parts in place, but also how lightweight and heavier small parts were grouped away from each other. Not sure what happened to that broken fan grille though; packaging was obviously not secure enough in that case. I don't recall where it was stowed in the packages I received.
So from experience in this sort of manufacturing (CNC laser operator for 10 yrs) the parts would be laser cut, folded on a press brake (yes manually, it's quicker than you think) Holes tapped, again manually, a clutched tapping head in a mill or drill press is sufficient enough. Please note that maybe the tapping would happen when the part was still flat if not in close enough proximity to a fold that would deform the said hole.
Off to powder coat where the tapped holes would be plugged with little rubber bungs. Then coated and cooked, then bungs removed, leaving tapped holes.
In my experience, tapping holes after powder coat not only chances the introduction of scratches to the finish, but also a possibility to break the powder coat around the holes and marring the finish.
I could be way out with Prusa's process, but that's how we used to manufacture our flat/folded stock and we used to makes anything from medical trolley bases to ice axe heads and Caribiners for DMM and internal components for Renishaw Metrology.
My 2 pence worth on the manufacturing side.
Scott
RE: The Core One Kit Waiting List
Absolutely this. I was involved in the production of many things in my time in manufacturing and nearly all of the tapping and folding was done manually. We would make batches of hundreds of component that were all manually folded, or tapped or had threaded inserts pressed into them manually using a pneumatic press.
Like you say, not everything is automated, u less you have an unlimited budget to buy the machine that does it, which is almost never 😅
Scott
RE:
Absolutely this.
I've always thought of Prusa to be the best there is when it comes to 3D printers, I've now learnt of some of their foibles, but nobody is perfect.
For Prusa to still command a premium for their products, they need to step it up for launch and not leave to the community to fix it after the fact.
Aside the delivery issues with damaged consignments, the problems seem to be relatively minor, but at this price point, you'd really expect none. Or am I being to critical of a £900 printer?
Scott
Edit: Sorry for the spam, just got back from a family meal 😅
RE: The Core One Kit Waiting List
I ordered Feb 2nd and I too don't have a batch number...just TBA. I contacted support and they said mine would probably ship out mid May. Didn't give me a batch number or anything just said mid may.
I ordered 3rd Feb, I'm batch 5, expected 14th May, but I do still have the filtration in my order, which is holding it back. So i would expect you to be in front of me in the 'queue'.
You got any other items in your basket that could potentially delay it? Buddy Cam and Filtration are the 2 main ones, unless you've ordered some filament that isn't going to be available until next Jelember?
Scott
I have nothing on my order, but the Core One kit now. About a week and a half ago, I removed all the accessories I had originally ordered with it. Extra build plates, nozzles, and such. Everything was still showing in stock at the time I cancelled, but just figured it was "safer" to only have the Core one. I asked support if me cancelling the items on my order moved me further back in the queue and they said "no". They said I'm in my original position in the queue, but didn't tell me what batch I was in just that they expected mine to ship mid may. Thanks for sharing your info.
RE: The Core One Kit Waiting List
Regarding: "they certainly do not have 100% production control (Quality Inspection) and so it could have passed. Fortunately, it can be easily repaired, an M3 tap is enough."
This is not specific to Prusa. Way back in the 1980's, most all industries suffered an infection called "Statistical Quality Control" (Brought upon the world by M.B.A. business types), which stopped inspecting every product, and randomly picked small samples. The profit bean counters had an easy sell (Look how much money we can save getting rid of the labor for 100% inspection). So most of the world these days does not inspect every item produced, they only inspect/test "statistical samples".
Now, for finished (fully built) products, some companies still perform an automated basic operational test for each TV or Radio or printer, but for individual parts and components, not so much.
In the fully assembled product, this is all handled during assembly and checkout, but in a kit where they only need to ship parts, it is not "Handled on the production line" for you.
Neal
RE: The Core One Kit Waiting List
Sadly, i assembled the printer and it fails on Y Axis.
Just bangs the nextruder endlessly on the front right side, until it crashes and restarts.
RE: The Core One Kit Waiting List
I have to say, although I'd like my kit sooner than later, as a newbie I'm glad I'm not in batch 1 or 2, as I'm not sure I'd be able to diagnose or fix some issues in poor instructions or QC failures from the factory. I want to thank everyone who is diving in and finding the bugs in the process for those like me, so I can have a smoother process when my kit finally comes in batch 7 (lol).