Mk3 to Mk4 its not a full upgrade. Not happy  

RE: Mk3 to Mk4 its not a full upgrade. Not happy

I think the hex pattern is there for coolness and want factor 🙂 but also for weight reduction of the part, of course.

RE: Mk3 to Mk4 its not a full upgrade. Not happy

The Mk4 is mostly the board and extruder, considering the Mk3s kit now has the thicker z frame thats more likely just a distance over time part adjustment.  Same as the thicker rods, 8mm over that distance isnt going to bend but if you can get 10mm, might as well do it.... they have said the head and board in the Mk3 would do very good results, we would be happy to travel down this route, only it leaves us with a board, LCD and a whole head to sell which dont feel is financially a great idea, so will be selling the Mk3s as is and replacing the whole printer (as its 3.something years old now).

RE: Mk3 to Mk4 its not a full upgrade. Not happy

Posted by: @sikkun

Personally I bought the full upgrade, plan on just buying a Bear kit and whatever couple other bits I need to have a second printer. 

Yeah this.  I have enough left over extrusion material on hand for at least one more Bear frame.  I would be interested in buying the leftovers from somebody who did the Mk4 upgrade, if the price were right.  I don't especially need another printer right now, but I could see building one for my brother, or to donate to the STEM focused charter school my kid will be attending next year.

RE: Mk3 to Mk4 its not a full upgrade. Not happy

Hello together, 

Didn't read the whole thread but I guess I got the differences between my MK3S+ and the MK4. 

I just want to express my opinion here for my special case. 

I got my MK3S+ kit at the beginning of the year for the full price. 

I guess there was nothing announced about the MK4. If I had know it, I would have waited for sure. 

I had several problems getting the printer to run  properly, so I wasted time until February or something. 

Meanwhile, I changed nozzles not only once, because of the long printing times (I don't want to leave the printer alone for longer time, because of the old wood house I live in). 

Was thinking about Raspi Upgrade and maybe Klipper, but I am not sure. Is it worth it? 

When I see the MK4, it brings so much cool upgrades. And I don't know if it is worth to upgrade my printer step by step. 

And now the MK4 is out, I will have a lot loss in money if I sell mine. Plus I need to finish my enclosure... 

Problem is I don't have the room for 2 printers. Even thinking about switching to Bambu or the new Anycubic, but I don't like their policy. 

I guess it would be fair if Prusa offers the full upgrade for a more reasonable price for people who where buying the MK3 maybe 9 moth ago. Maybe with the option to send them all used, old parts in as spares to repairs for customers that keep the MK3 standard and to get a good discount. 

I hope you understand a little bit of my frustration. I don't know what to do. 

Thanks 

Reno 

RE:

Similar boat here. I purchased my new MK3S+ kit in the Black Friday sale least year. Built it over Christmas. Now that the MK4 has been released I feel it’s a good upgrade, mainly due to the lack of first layer manual calibration - that and the fact I always like to have the latest! Lol. Yes its a little unfortunate that a new model was released shortly after a brand new purchase of what is now the predecessor, but that’s how it is when it comes to tech!

Rather than upgrading, I decided to purchase a new MK4 kit but like you, I have no need, and do not have the space in my office for two printers. Fortunately, my decision was made easier since I managed to sell my MK3S+ to a colleague, and will be dropping it off to him his week, for a very good price - so I’m only paying a little extra to get the full MK4 kit.

Try listing yours on your local boards and see how much you can get….

Posted by: @reno1986

Hello together, 

Didn't read the whole thread but I guess I got the differences between my MK3S+ and the MK4. 

I just want to express my opinion here for my special case. 

I got my MK3S+ kit at the beginning of the year for the full price. 

I guess there was nothing announced about the MK4. If I had know it, I would have waited for sure. 

I had several problems getting the printer to run  properly, so I wasted time until February or something. 

Meanwhile, I changed nozzles not only once, because of the long printing times (I don't want to leave the printer alone for longer time, because of the old wood house I live in). 

Was thinking about Raspi Upgrade and maybe Klipper, but I am not sure. Is it worth it? 

When I see the MK4, it brings so much cool upgrades. And I don't know if it is worth to upgrade my printer step by step. 

And now the MK4 is out, I will have a lot loss in money if I sell mine. Plus I need to finish my enclosure... 

Problem is I don't have the room for 2 printers. Even thinking about switching to Bambu or the new Anycubic, but I don't like their policy. 

I guess it would be fair if Prusa offers the full upgrade for a more reasonable price for people who where buying the MK3 maybe 9 moth ago. Maybe with the option to send them all used, old parts in as spares to repairs for customers that keep the MK3 standard and to get a good discount. 

I hope you understand a little bit of my frustration. I don't know what to do. 

Thanks 

Reno 

RE: Mk3 to Mk4 its not a full upgrade. Not happy

Hi

The Mk3s works well (we had one since 2019 with the MMU2s), the Pi addon would be good as gives you more than the Mk4 can do with the PrusaLink built in.  As the Pi is a computer it has storage which the Mk4 doesnt, its always WAY faster with PrusaLink (based on the Pi being a PC).  Also the Pi has a camera connector (something the Mk4 lacks) so you can add one way easier.

You can also use Octoprint (with a Pi) we have a Pi Zero will are selling (ready to plug in to an Mk3) with i think 32Gb storage, however its likely not fast enough to run a camera as well as its the Zero, not the newer Zero 2.

RE: Mk3 to Mk4 its not a full upgrade. Not happy

I have been thinking about purchasing an MK3S+ and upgrading it to an MK4 later on. Currently, I already own an MK3S+ and once I upgrade, I plan to use any spare parts to refurbish my original printer. While I haven't done the calculations yet, I am aware that upgrading this way can be expensive. However, with a fair number of extra parts, I hope to give my old printer a new lease of life.

Just thought I'd share some thoughts for anyone who needs a new printer faster and wants a positive outlook. 

RE: Mk3 to Mk4 its not a full upgrade. Not happy

Posted by: @flex

It looks like the upgrade does not include the stiffer frame, it adds vibration dampening. Also does it include the Thicker Z-Axis Rods? If not its not a truly MK4.  Not sure why both are not included for the price it should. 

This product includes:

32-bit xBuddy board (same as MK4)

Metal xBuddy case (and cover)

xLCD screen (same as MK4)

Nextruder parts (including E motor)

Cables for Nextruder, Heatbed, xLCD

10 mm smooth rods (Z-axis)

X/Y/Z motors Expansion joints for Heatbed

New belts for X & Y axes

Fasteners and other accessories

Filament for printable parts

Parts kept from your MK3S/MK3S+

Frame and extrusions (new MK4 has just a different look)*

PSU** (same wattage/voltage as MK4) Heatbed MK52 24V (thermistor and power cables will be changed) *

X/Y rods and bearings

*Frame and heatbed are not included upgrade, because replacing these parts brings no funcional advantage and would only increase the price of the upgrade.

If for some reason you still want a new frame (it has hexagons on the other side), it will be available on the eshop as a spare part.

**Please note that silver PSU will require a cable adapter. More information will be provided later.

RE: Mk3 to Mk4 its not a full upgrade. Not happy

The new frame is definitely much more stiffer than the previous one, of course if the similar material properties are maintained. Also it looks like a die casted. Die casting usually has huge cost benefit for  the large quantities manufacturing and a lead time. I am sure that frame design change was performed both from improving frame stiffness (mechanical aspect) and cost reduction/ lead time improvement. 

RE: Mk3 to Mk4 its not a full upgrade. Not happy

Curious how you are estimating stiffness.  Are you flexing it and gauging deflection?  Or, have you actually measured some deflection under load, etc?   I agree that cost savings seems more likely reason than structure, but I would love to know more!

Thanks,

Ben

RE: Mk3 to Mk4 its not a full upgrade. Not happy

Have you printed with both?  Is the quality of any significant difference?

Posted by: @gregory-verba

The new frame is definitely much more stiffer than the previous one, of course if the similar material properties are maintained. Also it looks like a die casted. Die casting usually has huge cost benefit for  the large quantities manufacturing and a lead time. I am sure that frame design change was performed both from improving frame stiffness (mechanical aspect) and cost reduction/ lead time improvement. 

RE: Mk3 to Mk4 its not a full upgrade. Not happy

Posted by: @gregory-verba

The new frame is definitely much more stiffer than the previous one,

Did you research that yourself or do you have demonstrable evidence that this is so,

I ask because Prusa states the following,

*Frame and heatbed are not included upgrade, because replacing these parts brings no funcional advantage.

RE: Mk3 to Mk4 its not a full upgrade. Not happy

Unfortuantely not

 I only own Mk3s+. Mine Mk4 kit (as others) didnt ship yet. These only my assumptions as mechanical engineer. 

RE: Mk3 to Mk4 its not a full upgrade. Not happy

I am NOT a mechanical engineer but I would think stiffness is also a factor of load so under light loads two frames could be equally stiff but under heavy loads one frame may prove stiffer.  If that's the case then first determining the max load the frame would be subject to and then comparing the stiffness of those two frames under the said max load would tell you if there is any print quality benefit from the stiffer frame.  But on an intuitive level I would also think a stiffer frame may not be better, since a stiffer frame would possibly transfer more vibration possibly adding ringing to the print.   But as was mentioned earlier the new frame may be cheaper to manufacture.

Again I am not an engineer and would welcome corrections and clarifications.

RE: Mk3 to Mk4 its not a full upgrade. Not happy

I think the question is whether the theory is reality.   

Posted by: @paul-hodara

I am NOT a mechanical engineer but I would think stiffness is also a factor of load so under light loads two frames could be equally stiff but under heavy loads one frame may prove stiffer.  If that's the case then first determining the max load the frame would be subject to and then comparing the stiffness of those two frames under the said max load would tell you if there is any print quality benefit from the stiffer frame.  But on an intuitive level I would also think a stiffer frame may not be better, since a stiffer frame would possibly transfer more vibration possibly adding ringing to the print.   But as was mentioned earlier the new frame may be cheaper to manufacture.

Again I am not an engineer and would welcome corrections and clarifications.

RE: Mk3 to Mk4 its not a full upgrade. Not happy

My guess is the new frame will make no noticeable difference, but time will tell once it gets in the hands of the users. I would be curious to know how much Prusa actually pays for the frames both the new and the old.  I can't imagine that it saves more than a few dollars. But I guess in a big run pennies add up.

I like the new hotend assembly but not enough to buy a new printer.

RE: Mk3 to Mk4 its not a full upgrade. Not happy

My guess (having engineering and CAD designers as clients) is its likely not how ridged it is, more will it resonate differently AND how will it warp when heated as it has a bed pushing 90oC upwards on to the frame.

RE: Mk3 to Mk4 its not a full upgrade. Not happy

Agreed.  Resonance is the problem and it’s quite possible that the new frame resonates less.  I just did a bear frame MK3 and the frame is several times more rigid and less resonant than the original frame.  VFA is noticeably reduced with the 20/40 extrusions in place of the cnc aluminum.  

I have a feeling that the injection molded frame is less resonant, especially with the honeycomb back. Rigidity is probably similar.  

Could be input shaping and the new motors negates any vibrations that affect print quality anyway. 

RE: Mk3 to Mk4 its not a full upgrade. Not happy

It is a little bit more complicated.

Stiffness or matrix of stiffness (cause it is different in different directions) is not related to load. It is divided from geometry and material properties.

Higher stiffness is related to higher first self frequency of the construction. For fast precise movement systems it is important to have higher first self frequency.

Low self frequency may resonant (very unpleasant situation) or input additional errors and shifts. Of course all of it may be calculated and simulated with proper tools.

Thats a little bit explaining why stiffness is important. 

Regarding the possibility of stiffer frame to transfer more vibrations, you need to ask yourself to where these vibrations are transformed and would you accept frame made from visco-elastic polymer (probably not) which has excellent damping characteristics.

Posted by: @paul-hodara

I am NOT a mechanical engineer but I would think stiffness is also a factor of load so under light loads two frames could be equally stiff but under heavy loads one frame may prove stiffer.  If that's the case then first determining the max load the frame would be subject to and then comparing the stiffness of those two frames under the said max load would tell you if there is any print quality benefit from the stiffer frame.  But on an intuitive level I would also think a stiffer frame may not be better, since a stiffer frame would possibly transfer more vibration possibly adding ringing to the print.   But as was mentioned earlier the new frame may be cheaper to manufacture.

Again I am not an engineer and would welcome corrections and clarifications.

RE: Mk3 to Mk4 its not a full upgrade. Not happy

Have you got any technical engineering testing and associated to support that statement?

They went to injection moulding to reduce the price of production and increate the rate of production.