Crimping

One of the most frequent method to connect terminals to wires is to crimp them. It need specific tools.

Using crimped ferrules or terminals for anything with power and for the mains

It is normal practice to never directly connect a flexible stranded wire to a terminal block. You shall crimp either insulated or uninsulated terminals (use thermoretractable sleeve for the uninsulated), and for use with terminal blocks, ferrules/sleeves. Unfortunately, insulated (automotive type), uninsulated and ferrules need different crimping tool, which are also different from the dupont crimping tool. Using low cost crimping tool needs a lot of strength and athletic capacities for a bad result. So again, a ratchet crimp tool may help for insulated automotive type. Ferrules are easier to crimp with non amplified crimp tool. For the mains, I have also used rigid wires, which don't need terminals. It is NOT normal practice for machinery, but I considered that the usage was ok with the limited vibrations of my printer. You may decide according local regulations for machinery.

Shown ferrule crimp plier is high quality Knipex 97 72 180, got for 29 Euros.

Insulated terminal ratchet low cost crimping tool Silverline PL55 bought for ~ 14 euros, shipping included. Silverline is poor quality brand, but this tool is ok for limited use, better than the basic tool sold with terminals asortments. This tool may need adjustment (see the teethed wheel on the side). Simple crimping tools as found in set of terminals is not recommended.

Dupont terminals

Dupont terminals are low cost and as the power carried in a printer is low, they could be used for anything except heating. The problem is they are quite difficult to crimp with ordinary pliers. So you need a ratchet type crimp tool and learn to use it. It is NOT recommended to solder, as this create a hard point which under stress, WILL broke one day. Molex connectors are better, but more costly. The same chinese ratchet crimp tool (SN28B) is sold everywhere at very different prices, so search a bit. Got on ebay for ~13 euros, shipping included. Note that to remove a dupont pin or plug, you need to lift the small plastic tongue locking it with a micro screwdriver.