There are 4 reasons for the problem:

1. The first layer is printed too fast

A: When printing the first layer, it is important to set a slower speed in order to allow enough time for the consumables to be able to bond to the platform. Generally when slicing, the first layer speed is set to 50% or lower.

2. Temperature or heat dissipation setting problems

A: Some plastics (e.g. ABS), which shrink more severely, will shrink differently due to local temperature imbalance when printing large objects, causing them to buckle and detach from the platform. If you print this kind of high temperature consumables, you need a heat bed, adjust the heat bed temperature to the right temperature (ABS, heat bed 100-120 degrees, PLA heat bed temperature 60-70 degrees), in addition, if your printer has a fan for blowing consumables, you can try to turn off this fan when you print the first layer.

3. Platform surface material

A: Different printing platform materials have different bonding effects; for this reason, try to use a variety of sticky substances to improve the adhesion of the platform surface, such as glue sticks, glue, dry glue, hairspray and so on.

4.Other situations

A: sometimes printing small objects, small objects do not have enough surface area to make it can be well attached to the print bed, the easiest way is to open the brim when slicing, or add draft to increase its contact area with the print bed.