Quality between Mk4 and XL  

RE: Quality between Mk4 and XL

I should add that this print is using 100% infill and is 1mm thick.

It does look a bit below par.

100% infill is almost always a mistake, there is no space to accommodate any variation.

Is this one of the earlier XLs with 0.6mm nozzles?   Make sure you are comparing like with like.  With 0.4mm nozzles my XL is as good as the best of my Mk3 prints, 0.6mm nozzles trade some accuracy for speed but still prfectly OK for most practical prints.

There are signs the filament is not perfectly dry, the XL is a little more sensitive to this.

Cheerio,

RE: Quality between Mk4 and XL

Thanks Diem, 

The Xl and the Mk4 are both sitting in my shed, and the filament may not be perfectly dry - it has been quite cold of late. The Xl has the 0.4mm nozzle, the same as the MK4. Would the sensitivity of the Xl to slightly damp filament account for such a large difference? The dampness of the filament should be the same between both printers, given that they have had the same filament for about 3 weeks.

RE: Quality between Mk4 and XL

These are test objects the I downloaded from the prusa website. I printed them in spiral vase mode. The one with the holes in it is from the XL.

That does look like damp filament.  If the filament starts damp then whichever printer used the spool first will get the wettest outer layers - but if it started dry the second printer will get the filament that has had more time to spoil.  The only fair comparison is with freshly dried filament in both cases.

I can't make a direct comparison as I don't have a Mk4 - but if there's any extrusion variation (eg due to water boiling in the hotend) 100% infill leaves no room for over/under extrusion to even out. 

At the startup and bed levelling stage *any* 'zits' on the XL print sheet are strong indicators of wet filament.  During the pause for heating it's worth knocking any damp generated ooze from the nozzle with a scrap of waste filament so there's no risk of a mini blob/pad distorting the mesh bed levelling.  I assume the case is similar for the Mk4.

Cheerio,

RE: Quality between Mk4 and XL

Thanks for that Diem. I'll try it again on the xl with a new roll of the same filament tomorrow. That should stop dampness from obfuscating the results.

Note:  New does not mean dry.

It was packed dry and often with dessicant but you have no way of knowing how long it sat in the wholesale warehouse, how long at the retailer, how it was treated there and in transit.  It is very common for new filament already to be damp.

Cheerio,

RE: Quality between Mk4 and XL

🙂 well I'll give it a go anyway. I'll post the result.

RE: Quality between Mk4 and XL

Today I used a new roll of petg filament in the xl. It is the same generic brand of filament that I used before, and the same filament that the mk4 has in it. The filament in the mk4, has been there for about a month.

I reprinted the same test job with the xl and the improvement was easily noticeable, as shown in the photo. 

The print from the mk4 is still better than the xl however. Is there somewhere else I should be looking, it is it still dampness in my new filament?

Both look a little damp.

There are signs of slight warping in the upper sample - make sure the print sheet is clean and that adhesion is good.

Cheerio,

RE:

Thanks Diem,

The upper one is the product of the XL, the lower one is the MK4. You're right about the signs of warping on the upper one, the bed was cleaned with isopropyl before printing, but, perhaps the moisture in the filament caused it to lift at the edges? As I said, it was a new freshly opened roll of filament in the upper test, but, who knows how it was stored, before spending a few months in my damp workshop.

Anyway, moving on, do I need to invest in a "dry box"?

IMO most people do better with a dehydrator.

Cheerio,

RE: Quality between Mk4 and XL

Your xl has something off with the hardware. Unfortunately you’ll have a lot of things to check. But this isn’t just a case of wet filament. Google xl and ringing. 

You will still need a dehydrator. Just letting you know that you unfortunately have other issues. 

RE: Quality between Mk4 and XL

I'm not surprised that there maybe other issues, but I thought I'd address one issue at a time. I've invested in a drybox (Sunlu S4), which should arrive today or tomorrow. I'll be able to ensure that my filament is totally dry then and move on to addressing any other issues.

I did contact Prusa support as well, but the person I spoke to, seemed to take a "shotgun" approach, wanting me to re-download and re-install the current firmware version and re-calibrate he docking station etc. I tend to prefer a "one thing at a time" approach.

RE: Quality between Mk4 and XL

My new Drybox has arrived, I'll commission the drybox today. How long should I wait, and what (if any) are the best drybox settings? The Drybox is a Sunlu S4.

It's a bit of a black art.  A near empty spool or one that has been exposed to the air for only a few hours needs no more than a couple of hours at 50°C.  Polyamides that have been exposed for weeks may need 12 hours or more...

I generally dry for a couple of hours after printing then store with dessicant (dried at the same time.)  That filament can be used straight from store for a few months, anything stored for more, and new spools, are generally dried before use.

Cheerio,

RE: Quality between Mk4 and XL

Thanks Diem, I haven't commissioned the drybox yet, a broken leg got in the way. I'll follow your advice when I do.