Saturday, March 13, 2021

Design lattice preparation for dobby

 Design lattice preparation for dobby:

* The technician should consider the below points before preparing the dobby lattice:

* What is the minimum number of legs  required for lattice?

* How many legs should get used in the dobby lattice?

* How many Heald shafts are there in the peg plan in the given weave.

* How many picks per repeat are there in the peg plan?

* What is the rotational direction of the pattern cylinder?

* What is the mounting position of dobby? 

* Since the lattice gets mounted on the pattern cylinder, and the pattern cylinder is an octagon so that the total number of legs in the lattice should not be less than 8.

 * A peg represents two picks. Now you have to make a lattice for a weave that contains four picks per repeat and you can not use the number of legs less than 8. In this situation, you have to make four repeats of your peg plan.

* Suppose that the peg plan contains 5 picks per repeat. How many legs in the lattice will you use. How many repeats of the peg plan will you use in the lattice. 

Lattice preparation for given peg plan:

We have taken a 5 end regular sateen as shown in the below picture. When we analyze the draft and peg plan. We find the number of Heald shafts used to weave a design and the number of picks in the peg plan.

Calculation of a number of legs in lattice and number of picks in the complete lattice:

* We know that our lattice shouldn't have less than eight legs. Our peg plan contains 5 picks per repeat. Mathematically we should use 2.5 legs to complete a repeat. Since one leg represents two picks so that it is not possible to use 2.5 legs to complete one repeat of the peg plan. 

* Now we will prepare two repeats of the peg plan on the lattice. It means 5 legs will be used to complete 2 repeats of the peg plan. 

* If we use 5 legs in the complete lattice, it cannot be mounted on the pattern cylinder because the lattice will be too short.

* If we make 3 repeats of the peg plan on the lattice, then the number of legs will be 7.5. This thing is not possible because you can't use half leg and the lattice length falls still a little bit short.

* If we prepare 4 repeats on lattice then the number of legs will be 10. it is more than 8 so that lattice will be enough long to mount on the pattern cylinder.

* If 4 repeats of peg plan are prepared on lattice then the number of picks in 4 repeats will be 20 and the number of legs will be 10 which is a whole number.

* Now it is clear that our dobby lattice will be prepared by using 10 legs and 4 repeats of the peg plan.


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