>as someone who has 3d printed nearly 100kg with FDM machines in the past year, I can't disagree more

If you run into problems, feel free to reach out to me. My telegram is in the medium article - I'll help you solve all your problem while extruding filament.

>even only looking at 'cheap' PLA, let alone PETG.

I don't extrude PLA or PETG at all, buying these special resins is difficult and costs 3x or 5x the ABS. I ask for the lowest wrappage and viscosity blend specially made for extrusion.

I buy general purpose polymers like extrusion grade granules of TPU, Nylon12 (it absorbs the least moisture in all nylons) and ABS - buy them from reputable companies they come in membrane sealed bags of 25kg. These polymers are mass produced and finding them for cheap around $1.4-$3 is easy.

>Filament widths are wildly inconsistent even within the same companies products -- this leads to extruder jams on the cold side.

Before jumping into making filament I researched on Amazon and found most filament being sold is within plus minus 0.05 to 0.02mm tolerance. Upon further research I found that these tolerances are trivial to achieve with sufficiently powered extruder and the industrial machines used for making medical grade silicone tubes can achieve plus minus 0.001mm tolerance using dual axis laser and feedback loop controlling pulling speed at high frequency.

You extrude fast, you lose tolerance. Companies might want more througput if their customers don't care about the dimensions and only want ultra cheap stuff.

I don't splice, all my filament is continuous length.

>I've received dusty spools that were vacuum packed, and spools that were vacuum packed with condensation visible on the inside of the packaging (humidity and moisture can damage many filaments, leading to lengthy rebake procedures if the filament survives at all.).

You need to seal the filament spool right after it's ready with a 10-20grams of dessicant. There are special vaccume seal bags and handheld vaccum sealer for low volumes like I am doing it's good enough.

>but the quality of your product must come from efforts you don't realize, because the quality on the market for cheap filament is

You'll have to troubleshoot the issues with your filament yes but once you've figured it out - it becomes easy.

I've written several part articles on my medium blog with many more to come where I'll write about common issues and their solutions.

I have had more difficulty in shooting down bugs in production code than building extruder. Just saying that skill level of a programmer and some random guy off the street might have difference. With some guidance anyone can do it.

My wife is now tuning extruder, filling the hopper and extruding filament as good as me. She doesn't have technical education background. Arguably, I find baking to more difficult than extruding filament, but it could be just that baking doesn't exite me.

I appreciate you concerns but quality of filament has lots of parameters but most common problems appear when:

1. Seller has bought the filament like PLA in bulk from china for $3-4 a spool. They buy a full container load at once to make it as cheap as possible. After a year on shelf even when placed in vaccum sealed bags, PLA becomes brittle. And you'll have very hard time printing with it - it will snap at different places randomly and your prints will fail.

2. Inconsistent diameter - these are extruding too fast or using low quality resin with no good operator on machine available for tuning. For example if I want to extrude 1kg filament and I add 200gram resin of A company, I ran out then I add 200gram resin or B company, you'll have to tune extruder again. Better create filament in large batches from the resin from same batch.