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Topic starter

So far everything I have lasts about 1 year

Then for some weird reason it stops either extruding

or selecting nozzle

Or just doesnt do anything at all

I am not a stupid person

I DO purge every time I change material as any one else does I am sure

I also started with 5 heads so I only use each one for a certain material

And still purge

Now I am down to just 1 working head

PETG And am scared to even change the colour

Yet I need to print with tpu




5 Answers

The Robox print head needs to be purged every 10-20 print hours when using PLA and ABS. This is due to the un-used nozzle and the fact that those materials degrade when not used. If you are using PETG you need to purge at least every 75-100 print hours or every material change, whichever comes first. Then you need to keep your filament dry. 

When changing materials, always purge at the higher of the two material temperatures. The Robox software will default to an average which is fine if you are changing between materials with similar temperatures, but if you change between PLA and ABS always purge at ABS temperatures. 

Always keep your filament dry, especially ABS and PLA. These materials will swell when hot in the heat inlet and jam it. 

The Robox print head is a consumable item due to its design. It is expected they will wear out over time. I get an average of 500-750 print hours per head, but I have seen them run as high as 1800 print hours. 

If you aren't purging PLA and ABS that will lead to material baked into the nozzles and heads that will stop the head from operating. 

I do not recommend keeping one head per material. I find that this does not solve anything and reduces the frequency of purging, which is essential for clean operation of the Robox print head. 

Have you opened support tickets? Have you attempted a manual purge? If you look at the heads that aren't working, do you see material leaking from above the nozzles?

@bhudson I do not recommend keeping one head per material. I find that this does not solve anything and reduces the frequency of purging, which is essential for clean operation of the Robox print head.
So Purging for colour doesn"t count???
Have you opened support tickets?
Tried that and as before my area has been whatever shut down and not allowed to contact support
Go figure
Sweden is neutral arent they
Yes its a VPN
And No I will not turn it off as I tell all the arseholes who think VPNs are bad

Topic starter

yet this is never mentioned anywhere I have seen either the higher temperatures or the need to purge if you do not change materials OR even worse the 20 hours So Ihave beeen stuffing my heads up by printing longer than 20 hrs without purging Quite often waaaaaay over that AND then being told It was my fault even though there are no guidelines for this in any of the cel material

Anyway back to pulling the head apart

What is the chance

AND I would bet zero

Of CEL releasing a complete instruction to dismantle a rebuild a head

Plus gasket sizes etc since we cant buy anything to fix them

AND do not say it is out of our capability because that is a reason to disclose it as we will fail and learn to but the heads from them

Jeesus just some real help would be good not just basic please provide all head details like hours and numbers etc etc before we begrudgingly give you a link to a video crap

give me details

shit give me the cad plans you lot cant buy them what am I going to do sell the plans to a competitor

Thats a laugh for everyone who owns a robox

And you never Know

Someone out here may have a contact to get things made

IF we knew what you need made

But that is a trade secret So pfrftt

END of rant

till next week

@jeffb The head design is protected. You can't buy several of the parts except for large orders which is the issue CEL is running into as they have explained.

The information you asked for with regard to the heads has been available for years and is on the support site under maintenance.

CEL will not release a head repair instruction. If you want to do it on your own go for it.

Having attempted it, it's not worth the time and you can't get the parts unless you are willing to buy thousands. The O-rings are 10.80 each with a minimum order of 5000 of I recall correctly.

Good luck.

And if they new about the failure rate as it seems they did why not buy plenty of stock to repair and or replace the heads as is now obvious


There are no such topic as "Maintenance" on the support portal. (

Can you please show there the Maintenance information are?

@bengt I just logged into the support site and did a search for "maintenance" and the articles all came up. You do have to be logged in though.


"on the support site under maintenance" is not the same thing as searching for the word "maintenance" that mostly gives you hits that refers to something you should do in the maintenance tab in Automaker. I get 19 hits and most are not maintenance but trouble solving. There should of course had been a true maintenance subject in the support portal but there isn't.

And note that none of the 19 search hits refers to something related to how to handle the heads as per the discussion above.

@bengt The purge temperatures are noted in multiple locations. The need to purge between materials is also noted in multiple locations. I thought the time recommendation was also noted but I haven't found it.
If you have only one material per head and you get successful purges from both nozzles at the start of every print you are fine and your heads just wore out. But if one nozzle stopped purging at the start of a print and you didn't act on it that would have been the start of a problem.

From what I have heard from CEL the seals are faulty. There is a little tiny O-ring seal around the needle valve stem and either a chemical such as the threadlocker mentioned above is getting in and destroying the seal in the O-ring or the O-ring itself is faulty.
This is from BHudson on an earlier post

@bengt @jeffB This information is very out of date. Further analysis found that the factory wasn't taking care with installation and a few seals were getting pinched. The S2 print head solved this issue.
Note that print heads always have been a wear item with limited life expectancy.

Topic starter

I have been looking at lots of earlier threads etc and it seems cel are deleting some of them and the thread this comment came from points to an earlier thread that has been deleted

SO its up to us to try and find a way of fixing these things with no help whatsoever from the bastards that stole our money and abandoned us to the wastelands

Where do we move the chat to from here cos there is no help here

@jeffb It's time for you to look for a different printer. Good luck!

Really?? All I am trying to do is keep my printer working And all i get is no information If the cost of repair to a head is so uneconomical then why hide the information Or conversely if the cost of parts for new heads is so exorbitant why hide the information like o-ring size and material And to say it is proprietary (that"s what you say when you want to protect your profit)when it is uneconomical etc is as stupid as it gets All I want is my printer to work (Buy a new head etc)or a way to fix it myself yet apparently that is out of the ability of anyone at the mighty cel workshops Why would you expect me to be happy when this is the way they do customer service

@jeffb There is a Facebook group, that might make you feel less like you're hitting a wall. I just dropped in to see what's new. :)
Some folks there are trying to keep them going with hardware and software mods, but the latter is in its infancy stages. It's not all doom and gloom, just don't expect new heads for a long time if ever from CEL because of the minimum order quantities req'd and component count, it really is an uneconomic proposition to remanufacture these now. I'm working away from home right now, but my E3D Revo Micro** conversion is almost complete...just a couple of thermistor wires to solder, heatsink fan to connect and lastly a couple of STL files to create for the rear head spring with a possible heatsink fan duct on the front. Ongoing works to incorporate the Cura 5 engine into AutomakerOS is pretty advanced, and if you have used Cura 5 there are some nice improvements over Cura 4.

** I swapped out the heatsink fan for a 12V version to avoid the DC/DC E3D PCB space requirements compromising the existing head casings.


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