Some dictionary gives “période de préparation et de nettoyage
“, “temps d’équipement”, “temps de préparation” and “temps d’apprêt”.

I think your own proposition is much clearer, but “réoutillage” isn’t in the dictionary (although as Gilles comments, it doesn’t mean it’s not a valid word). So I would propose “temps de changement d’outil” as an alternative.

I think the term would be

Temps de changement de série

or

Temps de changement de production

As you program you tool chain to produce a serie.

It is the terms employed on the wikipedia page of the SMED method in French.

The IATE database (European Union terminology database) has entries for Rüstzeit:

• temps de démontage (dismantling time) for Abrüstzeit in labor law (« temps nécessaire au démontage d’une machine une fois la production terminée »);
• temps d’apprêt ou temps de préparation ou temps d’équipement (set up time) for Aufrüstzeit in labor law;
• période de préparation et de nettoyage in agriculture;
• temps mort (idle time) in technology (« partie du temps utilisable pendant lequel on ne fait pas travailler l’unité fonctionnelle »).

IATE does not have an entry for retooling (in this sense). The word réoutillage is not present in standard dictionaries (it is neither in the Trésor de la langue française nor in the Petit Robert). Nonetheless, the word outillage is standard, and the prefix re- is very productive, so using the word réoutillage is not a problem in itself. What is more problematic is that most of the uses I find online are about retooling a factory in the sense of buying and installing new equipment, not in the sense of adapting the existing tools for a new product. This seems to be the case in English as well, though. Most of the examples in the Linguee dictionary have retooling translated by réoutillage. Linguee doesn’t have a German to French translation, but the German to English translation list suggests (re)tooling time (hence temps d’outillage or temps de réoutillage, though I don’t find this meaning of the word outillage in my dictionaries) or setup time (hence temps de préparation).