1, according to the official information of the Mechanics of Materials Network, replace the needle: if the needle pulling force is not enough, it may be the quality of the needle itself, you can try to replace the needle with a high quality.
2, adjust the depth of the needle: the depth of the needle is too shallow can also lead to insufficient pulling force, you can try to adjust the depth of the needle.
3, replace the needle holder: the needle holder may also have problems, resulting in insufficient pulling force, you can try to replace the needle holder.
4, check the needle and syringe match: the needle and syringe match is not good will also affect the pulling force, you can try to replace the better match of the needle and syringe.
5, check the needle fixed way: the needle fixed way is not correct will also affect the pulling force, you can try to check the needle fixed way is correct.