| HotFlo! | Implementation | |
In theory, you should be able to retro-fit a hot sprue system into an existing die casting die. In practice, it rarely proves practical. The dimensions of the die blocks and the location of the sprue, ejectors and cooling channels will usually prove to be less than ideal. The fitting of spacers or inserts is usually unsatisfactory.
It is easy to convert from a hot sprue system to a cold sprue system, but not the reverse.
The selection criteria for a hot sprue trial usually turns out to be "your next new job". This is very realistic because we have not yet found a component where a hot sprue system could not be used.
This will enable you to design the die to take advantage of all the benefits of a hot sprue system. People can learn how to do it, and the results can be evaluated.
If the project is on a very tight (unrealistic?) lead time, then it may not be the one to use to trial new technology. You need to bring people up to speed. They need to learn the small differences in operating procedures.
In practice, there is no lead time penalty with a hot sprue system, but it would be better to start with a job that has a realistic time frame - particularly with regard to die design and its sign-off.
Unit dies have a common die block (bolster), into which different die cavities can be fitted.
A hot sprue system can be used in a unit die, but the same comments apply about retro-fitting. Where there are a number of existing die cavities, it may be possible to make a new unit die holder for a hot sprue. However, the existing die inserts will probably have large trapezoidal shaped runners. They will either have to be blended to meet the circular runners of a standard hot sprue, or else a special hot sprue will have to be made.
The best way to implement a hot sprue system in a unit die is to design it in right from the start. The dimensions can all be optimised, and full advantage can be made of the new technology.
Hot sprue systems are very well suited to components which have an internal hole through which it can be gated. The compact nature of a hot sprue, and the advantage of shorter flow paths in the cavity make this a winning combination. It these applications, a special version hot sprue is usually required, by this is easily offset by the benefits. We have extensive experience in these applications and will be pleased to assist you in your evaluations.
There are some die cast components which present multiple technical challenges for any methodology. These may include extremely thin wall sections, short gateable lengths, obstructions to metal flow in the cavity, deep narrow blind cavities, lack of venting area, and thin cavity upstands.
A hot sprue system will give you a number of advantages in casting these types of components so you should definitely go ahead and use it. However, people in your organisation need to be aware that the technical difficulties in casting these types of components are usually not related to the hot sprue system.
So, a judgement needs to be made about the appropriate component on which to first trial a hot sprue system in your organisation.
The biggest challenge in implementing a hot sprue system is usually not the technology at all, but the human factors. It requires a broad consensus and understanding across multiple levels in the organisation; senior management, engineers, production management, tooling staff and production operators.
It does require a few changes in design and procedure, and, although these are quite minor, all changes will meet some resistance.
Organisations that have a progressive approach, and a will to get ahead of their competitors are the ones that gain the most from this new technology.
| Issue | Date | www.hotflo.com |
| 1 | 14th November 2001 | 7 criteria defined. |
 |
|
 |
|||||