为什么何时可以剪裁？

Forming taps produce strong and cost-effective threads

通过形成，您必须同时控制二维，即次要直径和螺距直径。集团

在许多机械车间中，创建线程是一种常见的做法。该过程的这一部分发生在游戏后期，经过大量工作以使组件接近完成后。这就是为什么必须正确螺纹的原因。一个失误和整个部分可以被报废，没人想要这个。螺纹内部孔的三种常见方法是挖掘，铣削和形成。

“It's very hard to entertain the idea of switching to thread forming if you’re not familiar with it or haven't been introduced to it in the past,” said Matthew Haid, application specialist,Dormer Pramet，埃尔金，生病。“大多数人认为您必须在一个洞中使用切割水龙头。而不是切割螺纹，而是形成水龙头将流入牙齿间隙而不是切割的材料。”

尽管切割方法往往是最受欢迎的，但线程的形成确实具有一些重要的优势，具体取决于应用程序。

“One of the biggest differences is that forming taps do not create chips,” said Kyle Matsumoto, product engineer,美国OSG，美国伊利诺伊州的圣查尔斯。“芯片疏散可能是螺纹时的巨大挑战，尤其是在深孔中，因此没有芯片是这种方法的优势。”

由于没有芯片生产，这种形成倾向于提供更高水平的安全性和生产率。它也往往更准确，产生正确的公差。

“It's also a stronger thread,” said Haid. “However, there are some limitations, like it does require more spindle power. And while it can be used for most industries, the food, medical, and aerospace sectors are exceptions.”

随着形成，水龙头将材料滚动，产生兔耳状的形状，其中包括缝隙而不是平坦的表面。对于某些行业来说，这可能是有问题的，因为差距可以收集污染物和颗粒。

Haid说：“形成的水龙头往往比其他方法长三到20倍。”“线程形成是未来的浪潮，但我不知道商店是否总是知道这是一个可行的选择。与之相关的有点前期成本，但是在许多情况下，扩展的工具寿命证明了成本是合理的。”

关于孔

随着形成，3H孔尺寸对于螺纹的整体准确性极为重要。许多不熟悉成型的操作员可能会寻找标准或传统的Tap Drill图表，但形成有其自身的要求。找到新的参考资料可能会很具有挑战性，但是许多切割工具制造商可以提供规格，并且浏览机器手册可以提供见解。

“The minor diameter cannot be controlled using forming taps, and therefore a tighter tolerance is required,” said Matsumoto. “If the drilled hole is too large or not as precise, this can limit the amount of material that is able to be displaced to properly form the thread. On the flip side, if the hole is too small, there will be too much material needing to be displaced, resulting in failure.”

在整个过程中，使用良好的Predrill孔尺寸并不断对其进行检查，尤其是在有很多孔的情况下，可以帮助创建高质量的线程。美国OSG

Forming has its own unique drill size, which tends to be larger than the standard cutting tap size. For forming, you want to drill the minor diameter oversized so that it’s slightly larger than what it will be when finished. When the forming tap is ground dimensionally, it will displace the material, which will squeeze into the full file of the tool, bringing it to the minor and pitch diameter.

“通过形成，您必须同时控制二维，这是次要直径和音高直径，”产品总监Mark Hatch说，集团，马萨诸塞州的西博尔斯顿。“这与切割方法不同，在敲击之前，您可以在小直径的最终尺寸上钻出最终大小。孔的大小是在进入孔的切割水龙头之前完成的。当切割水龙头是地面的时，未成熟的直径是间隙，因此与未成年人没有接触。”

If there isn’t good, smooth flow of the material, it can become very difficult to control the size and create the correct thread.

The experts recommended using a good predrill hole size and checking it constantly throughout the processes, especially if there are a lot of holes.

“You definitely want to make sure that the first hole is the same diameter as the last hole,” said Haid. “That way, you have a consistent hole all the way through so that you can then form. I would also recommend checking the hole and threads after the first form. Do one first and check it right after, so you can save yourself a lot of downtime.”

Material Matters

材料类型和硬度在形成的有效性中起着重要作用。如果材料太脆或硬，则可能使形成过程不可能。

Matsumoto说：“铝，不锈钢，碳钢，一些合金以及基本上有40 hrc的任何材料可与这种方法搭配得很好。”“我们已经测试了诸如耐热超合金，特别是Inconel 718之类的事物，并且效果很好。问题在于，这些类型的材料通常用于未被广泛接受线程形成的行业，因此除非是一种特殊的工具，否则为这些应用制作成型水龙头并没有真正的意义。”

工件材料必须具有流量的能力，才能创建线程配置文件。铸铁等材料应使用切割方法来产生螺纹。

Haid说：“由于其导热率非常低，钛也可能是一个挑战，这意味着它不会很好地吸收热量。”“如果没有必要的热量，材料可能会很难流入螺纹空间。但是对于钢和铝，它是创建线程最强，最准确的方法之一。”

The experts noted that for small-diameter threading applications in difficult materials, cutting threads can be problematic because the chips tend to be very strong and do not evacuate easily, leading to tap breakage. This is not an issue with forming.

形成会产生更强的线程，但需要更多的主轴功率。虽然大多数行业都可以接受，但食品，医疗和航空业是例外。Dormer Pramet

“Another advantage of forming is that it is not shearing the grain structure,” said Hatch. “So when it displaces the material, it compresses the root of the thread profile and you get very smooth thread flanks, providing increased dynamic strength.”

Coating technology also plays an important role in the performance of the forming tap. The workpiece material will dictate the appropriate coating needed for the tool.

哈奇说：“由于涂料与材料的组成之间的化学相互作用，必须正确匹配它们。”“例如，如果我要在6061-T6铝中使用镀锡的形成水龙头，则锡涂层实际上将与金属有化学相互作用，并开始与该工具粘合。这将产生非常差的结果和较低的工具寿命。因此，您将在铝中使用的内容与不锈钢等应使用的东西非常不同。”

Machining Factors

Matsumoto说：“由于切割动作，线程铣削和螺纹敲击具有较低的扭矩规格。”“但是，随着螺纹形成，置换材料所需的扭矩要大得多。这意味着商店可能需要考虑更大，更强大的机器。”

The experts agree that one of the errors shops make is underestimating the power required to drive a form tap.

“A forming tap requires about twice the torque compared to a cutting method,” said Hatch. “As the tap sizes get bigger, it makes less sense to use forming. By the time you get ¾ to 1 in. or above, the use of forming tends to drop because it requires a machine that can produce a lot of torque in order to efficiently run it.”

此方法非常适合高生产的CNC加工，可以实现该可重复性和一致的线。

“It’s also so important to have a nice rigid setup,” said Haid. “The machine needs to have the power, there needs to be a strong toolholder, and the workpiece needs to be secure. Everything has to be dialed in really well.”

推荐的速度要比传统切割水龙头要快得多。这可能是令人生畏的，尤其是当您没有听到并看到剪切方法所获得的常见线索时。

Hatch指出，形成的优势之一是它对灯出的操作非常有效。

One of the strengths of thread forming is that because it doesn’t produce chips, it works well for lights-out operations.集团

“Because there are no chips, you are able to get a very consistent, predictable thread on unattended operations,” he said. “If you get a very good-quality tool, you can also get a very predictable tool life result. This will help shops move into the automated processes and allow them to run unattended.”