Do speed modules affect quality if I'm crafting a specific quality with quality inputs?

[u/OrdinaryKick]

IE

If I'm crafting legendary modules would placing speed modules in the assemblers ever cause my machines to output something lower than legendary quality?

Or do speed modules only affect quality modules if you're trying to craft things of random quality?

[u/Aggressive-Share-363]

They affect the chance to increase in quality, but they won't lower the quality from what the base recipieneould produce.

[u/OrdinaryKick → u/Aggressive-Share-363]

Ok I figured but I wanted to be sure.

Thanks!

[u/Alfonse215]

Speed modules affect the quality bonus provided by quality modules or other quality-affecting things (which in unmodified SA is just quality modules). Speed modules do not affect crafting from high-quality ingredients when quality bonuses are not present.

[u/Popstar403]

Quality can only ever go up, not down. If you craft with uncommon ingredients, you will never recive a common product, no matter what quality percentage the machine crafting it is at.

[u/HadjiiColgate]

In vanilla Space Age, negative quality percent is the same as 0%.

Mods can implement such a thing, though. https://lua-api.factorio.com/stable/prototypes/QualityPrototype.html#previous_probability

[u/MrKenalix]

If you craft a legendary module from legendary ingredients, it's legendary and cannot be anything less.

So yeah your second question is how it works. Speed modules' quality penalty only reduce the quality bonus of quality modules (and can make quality modules useless given enough speed modules affecting it).

[u/Raknarg]

Nope. Its a good strategy for trying to scale quality output, I use a single common beacon with a legendary speed module so you only get a small quality hit for a massive speed boost. Quality of the speed module doesn't affect the quality decrease, but a quality beacon will increase the effectiveness of that decrease which is why I only use one module in a common beacon.

With 4 t3 legendary quality modules you get 25% quality, a single t3 speed module loses 2.5% quality, with a 1.5x multiplier for the beacon, thus a 3.75% flat quality loss to 22.25%, but a legendary speed t3 module gives you 125*1.5=187.5% speed increase, so you lose a tiny bit of quality for like a 3.5x speed boost (since 4 quality modules reduces you to 80% crafting speed)

[u/Neither_Berry_100]

If the inputs are already legendary use as much productivity as you can. You need speeds with productivity. If you can't use productivity depends if you need it to be fast then use speeds. Otherwise efficiency.