Filament tolerance?

Could someone point me to the location in the reprap spec for filament tolerance? My searches show folks talking about 3 mm filament being +0.0 and -0.3mm, and +0.3mm and -0.3mm, 2.85 +0.15, and several other values. But I can't seem to find an actual spec that says "Rep is designed to accept filament 3.0 mm +x and -X; or 1.75 mm filament +X and - X"

Is there a formal spec for filament tolerance?

Reason is I have a spool of 3.0 mm filament that is 3.6 mm in places, and of course jams the extruder, and I want to know the actual spec.

Well, good luck finding that.... You just got a bad quality filament.

When purchasing filament you need to check the vendor specs and really hope for the best, stick to the good suppliers.

For real specs a 3mm hotend will take filament up to 3.2mm and a 1.75mm one will go up to 2mm filament, anything beyond that will jam it.

Contact the supplier that sold you that spool, and request a refund or a new one.

.6 over is insane.
Buy some better filament!
Mine is within +-.1mm for the most part.

Here is a review of filament. This is 1.75mm filament in both cases. The premium filament had a higher variance but printed better. The cheap filament had lower variance, but needs a higher temp for the same result.


As I recall the max variation I measured (Measured 5 meters of each spool every 10cm) was .06mm so filament could go as low as 1.69mm or as high as 1.8 ~ 1.81... Used a paper gauge that is accurate to within .01mm. if your getting anything in the .1-2mm tolerance or higher, then you need to return the crap. My $15dollar filament had a variance in the .05mm range.......

---

My Personal Blog. Build blog.
[engineerd3d.ddns.net]

Modicum V1 sold on e-bay user jaguarking11

So again, what it the actual spec, what reference can we point at to say this is how big and how small is acceptable for the filament?

To say "For real specs a 3mm hotend will take filament up to 3.2mm and a 1.75mm one will go up to 2mm filament, anything beyond that will jam it." if dandy, but this is not any type of spec, its one person's observation.

To have the opinion " .6 over is insane." is also fine, but what is the actual spec? I would like to be able to check is a give manufacture claim any kind of tolerance to any specific spec.

So, there is no actual spec filament size?

Thanks!

There is no spec as it applies to the printers. Variation in filament diameter translates to variation in the width of the line laid down by the printer and that translates to print quality and accuracy. There's no spec for any of those other than what you consider acceptable. Most printers have a lot of other factors that affect print quality as much as filament diameter so isolating effects that are specifically caused by filament diameter variation from all the other things would be very difficult unless the filament is really awful.

Most manufacturers seem to have variation in diameter pretty well controlled, but absolute diameter still varies a bit. You can compensate for that by measuring the filament at multiple places and using the average value for the filament diameter in the slicing software or when printing if you use volumetric extrusion.

The spec for filament in "Reprap" terms exists only insofar as 1.75mm or 3mm filament. This specification dictates a number of features or parameters on your machine, in particular to do with the hotend. This in turn drives the filament manufacturers to supply to these two sizes. How well they produce their filament then determines any variance you might find.

For 3mm filament expect to find variances ranging from 2.5 through to 3.6 on bad quality filament (as you have discovered, although that is quite extreme). Reaonable quality filament will usually have far less variance, in the region of 0.1 - 0.2mm for the most part, sometimes less. I use a single supplier in the UK and they are pretty much within the 0.05 range supplying 3mm filament that varies 2.94 to 2.98/2.99 on the roll i just checked. Thats why i use them and no one else.

The comments above by other posters also stand true, especially the_digital_dentist's comment about other factors on the machine, but yes, crap in == crap out, bad filament is a good mistake to avoid. HTH