![thread milling feature cam multiple lead thread milling feature cam multiple lead](https://i.ytimg.com/vi/iFG5LN5SRsQ/maxresdefault.jpg)
In this way, each lead is being cut with a tool having practically the same amount of wear. If a thread gauge is in the form of a screw on GO/NO GO gauge and it won't start, which lead is incorrect? To overcome this, I've created a threading cycle, where one pass is taken successively on each thread lead until finished.
![thread milling feature cam multiple lead thread milling feature cam multiple lead](http://www.harveyperformance.com/wp-content/uploads/2017/05/multi-start-thread_2.jpg)
In multi-start threads where quite a lot of material is removed to form each lead, if each lead is cut separately, each successive lead will be cut with a cutting tool that has more wear than it had when cutting the previous leads. In a two start, 3.0mm pitch thread, if the first lead is cut with the tool starting at 6.0mm from the end of the thread, the start point for the second start would be from Z9.0. In this way you won't move the error zone onto the actual start of the thread. Generally its better, if space allows (there may be a tail stock in the way) to move the tool further away from the start of the thread, rather than closer to. I'm pointing this out, because you must be mindful of this when repositioning the tool's start point for successive thread leads. There are formulas to apply to calculate the length of both the acceleration and deceleration error zone. This erroneous lead area is easily overcome at the start of the thread, if the tool is able to start at any distance from the start of the thread, but is more difficult to nullify at the end of the thread if threading to a shoulder. In all thread cutting involving the treading tool's travel synchronizing with the spindle rotation, there is an area at the start and end of the thread, when the machine slide is accelerating and decelerating respectively, where the lead will be erroneous, and is directly related to the feed per revolution of the slide and the spindle revs. Therefore, to cut the 2nd start, the start point for the threading tool is moved in the Z axis by 3.0mm, either closer to, or further away from the start end of the thread being cut. Take, for example, a two start thread having a lead of 6.0mm. Some controls have an address function to index the thread for the 2nd and any successive leads of the thread being cut, as indicated by cadcamwiz, but what works on all controls is to shift the start point of the threading tool by a distance equal to the thread lead divided by the number of starts. Thanks!Cutting a multi-start thread is relatively easy.
![thread milling feature cam multiple lead thread milling feature cam multiple lead](http://s526712518.onlinehome.us/wp-content/uploads/2014/05/DSC04249b1.jpg)
My question is how would I format these programS to do this? Or would I need special tooling for this? I'm just trying to better my self for the future and learn and also try to increase productivity with my machines.
#Thread milling feature cam multiple lead manual#
We have been cutting our 5/8-8 and up acme threads with a die head on a manual lathe after it is machined in a leadwell cnc lathe with a fanuc controll. I'm currently a programmer for my company and I'm straight out of trade school,not to much experience I've been with my company for about eight months and I'm in charge of all the machines in our shafting cell.