CONVEYOR BELT HOT SPLICING

We have discussed already in previous post about the required tools and resources for hot splicing of a conveyor belt. We have also discussed the basic concept of hot splicing as well as we have seen how to secure the center line of belt ends. 

We have also discussed some quite important factors that must be considered during hot splicing of conveyor belt. You may find my previous post by following links. 

I will recommend to study by clicking following link and after that read this post for clear understanding of hot splicing of conveyor belt.

Conveyor belts hot splicing and vulcanizing: tools, equipment and resources

Conveyor belt hot splicing procedure

So let us start the splicing of belt end

So we have drawn the center line of belt end and we have also secured the belt ends by belt clamp as we have seen in previous post. Now we will have to make splicing steps at both ends of belt. First we will start with bottom end of conveyor belt.

We will fold the upper end of belt to carry out the splicing work for bottom end of belt smoothly. As we have discussed above, we will have to cut one bias cut of dimension of 0.4 x B at bottom end of belt, where B is width of conveyor belt.

Fold the bottom end of belt as displayed in figure and mark one line 25 mm behind and parallel to the bias cut as shown in figure. Cut the rubber cover with the help of knife (held at an angle of 45 degree) along the marked line to remove 25 mm width of rubber cover to provide the future joint gap. During cutting of rubber cover we will have to give care as fabric ply should not be damaged. We will use pincers to remove the belt as stated above.

Now we will have to fold again the lower end of belt to mark the splice length and step length as well as we will draw one parallel line to splice length line of having width of 25 mm, cut and remove rubber of 25 mm width belt in order to provide future joint gap. During removing rubber of future joint gap, we will have to take care that fabric ply should not be damaged.Specifications of splice length and splice steps length could be taken from given table of splice specifications for fabric ply conveyor belt.

Splice specifications for fabric ply conveyor belt 

Now remove fabric ply by cutting in starting point and pulling with the help of ply puller.

Now we will also remove the ply from upper belt end in respect of lower belt end.

Superimpose and align both belt ends, if there is any excess portion of upper belt is coming over lower belt end then cut that excess part of upper belt end.

We must have to check that belt ends edges are properly aligned with each other.

Joining of belt ends

Once we have splice steps and length at both end, we should follow following mentioned points.

 As we have secured both end of belt with specified splicing, now we will use buffing device to clean the surface and edges of both ends of belt. Buffing could also be done easily by using buffing wheel with grinder as shown in figure. 

Clean the surface carefully; there should not be any dust or foreign particle. Buffing dust should also be cleaned by fresh soft brush, Do not use rough brush.

Now stir the splicing solution and open the splicing solution, use soft brush and use solutions throughout the splicing area and joint gap.

Once splicing area of both end of belt is completely covered by splicing solution, we should leave both ends for at least 30 to 35 min for drying. We should again use splicing solution smoothly and evenly over the splicing area second time and again leave for 20 min for drying . If it is sticky we may go ahead.

Now we will have to use uncured tie gum rubber over the splicing area and we must care that air should not be entrapped , now move roller over the uncured tie gum rubber and remove the protective sheet.

Use uncured tie gum rubber for filling the joint future gap also.

Now we will have to superimpose the both belt end i.e. top end and bottom end with each other but we must take care that air should not enter between both ends of belt s well as both belt ends should be in same center line that we have drawn earlier.

We have to also fill the joint future gap of carrying side with the help of uncured tie gum rubber.

Now we will have to cover the complete splicing area by brown release paper.

And finally we will place the splicing area between both heating plates of hot vulcanization machine. Hot vulcanization machine plates should have capabilities to cover splicing area completely. Vulcanization machine plates should be 2 inch larger than width of belt and 4 inch larger than length of splicing.

Tighten the clamping fasteners of vulcanization machines plates

Provide desired pressure approximate 100 to 125 PSI 
Vulcansing temperature must be approximate 145 C

Once the vulcansing temperature achieved, we will have to cut the power supply and we will have to stop the heating. We will allow the belt to cool under same pressure of 125 PSI.

When temperature becomes lesser than 50 C , we will have to remove the vulcanization machine and we will carry out the inspection and dressing work of joint of belt ends.