inflexibility

[paulsroom @paulsroom My Robox is a Blue Commercial Version Chichester, UK]

Having recently performed a manual purge to clear a blocked nozzle, my Robox began printing okay without any problems. Whether or not this procedure is good practice, there was no other way of clearing the nozzles. So having subsequently printed a range of models all resulting in a good surface finish and no extraneous stringing or incorrect shapes. I decided to try out the newer materials of nylon and TPU. TPU was of special interest for me.

The first print with nylon was a complete mess. It started off okay but half way through it no longer printed the shape and at the end half the filament extruded was stuck to the nozzle. I was thankful that I had chosen a small model just to see how it printed.

I haven’t got started with the TPU because it’s so flexible that I can’t feed it in far enough for it to be grabbed and fed into the print head. It has the sound of reaching the extruder but it won’t pull through. At first I thought maybe I have another blocked nozzle. But when I tried to load the more common filaments such as PLA, ABS and nGen, they all loaded okay and ejected okay.

So I wonder, have I wasted my money in buying these two filaments? How is the TPU loaded if its flexibility simply causes it to bend back at the feed aperture next to the smart reel. I’m assuming that others have not had such problems, so what is the secret?

[BHudson @bhudson I have both RoboxDual and other Robox versions Arizona, USA]

@paulsroom You need a gray V2 extruder to print flexible filament. Then you insert a section of Bowden tube into the filament feed port and feed the filament through that. NinjaFlex isn’t detected a lot of the time so I have to turn off filament detection. NinjaFlex also requires a specific profile for both the material and the print.

I have good luck with PolyFlex using the above loading method and a V2 extruder.

I use Taulman nylon and don’t have any feed problems. If you have feed issues, you may need to look at your temperatures.

I operate two Betas and four Production Robox.
I am the US/Canada Technical Support engineer for the Robox.
See my 3D Hub site at https://www.3dhubs.com/phoenix/hubs/ben

[paulsroom @paulsroom My Robox is a Blue Commercial Version Chichester, UK]

@bhudson The nylon loaded okay and ejected okay. It was the print that failed totally. Since everything had been working fine, I was rather disturbed to see that half the filament had printed and the other half was stuck to the nozzle. So I’ve paused printing in nylon for the moment to see if any other problems arise generally.

The only grey extruder - by which I assume you mean the print head - is a dual filament one shown in the CEL shop. Does this that TPU can only be printed on the dual filament Robox?

• This reply was modified 5 days, 3 hours ago by  paulsroom.

[BHudson @bhudson I have both RoboxDual and other Robox versions Arizona, USA]

@paulsroom Gray extruders are V2 extruders, which are not specifically for dual material use. They are for all material use. Black extruders are V1 extruder and do not handle flexible filament. Any printer with a gray extruder or that has been modified per the CEL instructions to convert a V1 extruder to flex use can be used to print flexible material.

Print failures partway through a print where the print splits are usually due to a bed or head misalignment that occurs during printing or due to a filament feed issue that causes a period of underextrusion. I suspect that your nozzle hit a warped area on the part and knocked the head or bed out of position, though without seeing the resulting print that is just a guess.

I operate two Betas and four Production Robox.
I am the US/Canada Technical Support engineer for the Robox.
See my 3D Hub site at https://www.3dhubs.com/phoenix/hubs/ben

[paulsroom @paulsroom My Robox is a Blue Commercial Version Chichester, UK]

@bhudson Yes I suppose there could have been a part of the extruded filament that protruded above the layers. That has happened before, but not regularly. I had another project on so I didn’t want to bothered with running different tests, but I am going to try again with the nylon.

With regard to the grey extruder for printing flexible filament, can I just confirm that I need the grey extruder as shown in the last couple of pictures in this support instruction…

https://robox.freshdesk.com/support/solutions/articles/1000074141-extruder-removal-and-assembly-video

….in which case do I then need to buy the RBX01-X2 Extruder ? I don’t see any other part on the CEL shop that makes the extra piece alone to fit. I have a RBX01-S2 (black) print head fitted but haven’t looked to see how the extruder looks.

[BHudson @bhudson I have both RoboxDual and other Robox versions Arizona, USA]

@paulsroom The gray extruder is a V2 extruder that is capable of printing flex filament. The black extruder is a V1 that is not.

CEL published files and directions to modify your V1 extruder to print flexible material. If you aren’t familiar with these, you haven’t done it and your black V1 extruder will not print flexible material.

If you have a black, unmodified V1 extruder, you will need to either buy the gray V2 extruder or modify your extruder to do flexible filament.

I operate two Betas and four Production Robox.
I am the US/Canada Technical Support engineer for the Robox.
See my 3D Hub site at https://www.3dhubs.com/phoenix/hubs/ben

[paulsroom @paulsroom My Robox is a Blue Commercial Version Chichester, UK]

@bhudson Thank you everything is clear to me now. I think it would have been a good idea for CEL to have added a word for the TPU filament to say that a different extruder was needed. While I’ve upgraded my Robox for some things and the software handles others, it would be a good idea if an automatic email was sent out to everyone when an important upgrade appears.

[BHudson @bhudson I have both RoboxDual and other Robox versions Arizona, USA]

@paulsroom In AutoMaker, the “i” symbol does that function now. The information has been on the website in various places and forms and mentioned here about a dozen times over the last couple of years.

I operate two Betas and four Production Robox.
I am the US/Canada Technical Support engineer for the Robox.
See my 3D Hub site at https://www.3dhubs.com/phoenix/hubs/ben

[paulsroom @paulsroom My Robox is a Blue Commercial Version Chichester, UK]

@bhudson I still feel that my criticism is justified. With all the information coming from all different sources all over the net, it’s desirable to have some things made very clear. There’s no reason why a link for additional information could not be added to the TPU filament page on the CEL shop site.

[Lee Bowman @leecel I have several commercial Robox units Portishead,Bristol]

@paulsroom, Your printer has been with us in the last year so there is a good chance your extruder is flexible compatible, if you remove the left black gloss side from your printer you can see the the extruder in the top left of the bay. If the extruder is half black half grey it has been updated, if it is all black then it has not.

Robox Support Engineer

[Mike @17bt CHORLEY, Lancashire]

If the extruder is half black half grey it has been updated, if it is all black then it has not.

Having bought a secondhand one recently, I was wondering if mine had been, and thank you for this comment. I now know mine has been too. Great stuff 🙂

[BHudson @bhudson I have both RoboxDual and other Robox versions Arizona, USA]

Please note that half-black, half-gray extruders in North America are not flex compatible.

I operate two Betas and four Production Robox.
I am the US/Canada Technical Support engineer for the Robox.
See my 3D Hub site at https://www.3dhubs.com/phoenix/hubs/ben

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