〜により used twice in the same sentence


Context: explanation of the [Friction Stir Welding
process](https://ja.wikipedia.org/wiki/%E6%91%A9%E6%93%A6%E6%94%AA%E6%8B%8C%E6%8E%A5%E5%90%88).
[![enter image description
here](https://i.stack.imgur.com/sZq1S.png)](https://i.stack.imgur.com/sZq1S.png)
In the fourth sentence I don't understand why there are two 〜により.

> ツールの移動 **により**
> 接合界面同士が順次[塑性流動](https://kotobank.jp/word/%E5%A1%91%E6%80%A7%E6%B5%81%E5%8B%95-90124)
> **により** 攪拌・一体化

What is that is causing the process? The movement of the tool or the gradual
plastic flow? My translation attempt:

> Thanks to the movement of the tool the joining surfaces become agitated and
> unite thanks to the gradual plastic flow.

Also, in the sentence ツールの回転に引きずられる形で塑性流動 could you explain if 引きずられる refers
the plastic flow being caused by the rotation of the tool or if it refers to
the rotating tool being dragged? Thank you for your help!




Your translation attempt is fine. Wording could be slightly different but that
is largely a matter of how you want the sentences to "feel". You understand
the meaning of により, although "thanks to" seems like a very colloquial way to
phrase it. I might choose "due to" or "because of" or perhaps "by (means of)",
although that's nothing but a matter of preference.

There are two により because the sentence references two things being the cause
of something:

> **ツールの移動** により = by/due to **the movement of the tool**

and

> 接合界面同士が **順次塑性流動** により攪拌・一体化 = the surfaces to be bonded are
> gradually/steadily/systematically stirred and joined together by **the
> plastic flow** (of the metal).

As for 「ツールの回転に引きずられる形で塑性流動」, it's saying that the method of "dragging by
rotation of the tool" results in the plasticity.

Thanks to @By137 for correcting my misunderstandings regarding "plastic" and
"method".




Your translation attempt is fine. Wording could be slightly different but that
is largely a matter of how you want the sentences to "feel". You understand
the meaning of により, although "thanks to" seems like a very colloquial way to
phrase it. I might choose "due to" or "because of" or perhaps "by (means of)",
although that's nothing but a matter of preference.

There are two により because the sentence references two things being the cause
of something:

> **ツールの移動** により = by/due to **the movement of the tool**

and

> 接合界面同士が **順次塑性流動** により攪拌・一体化 = the surfaces to be bonded are
> gradually/steadily/systematically stirred and joined together by **the
> plastic flow** (of the metal).

As for 「ツールの回転に引きずられる形で塑性流動」, it's saying that the method of "dragging by
rotation of the tool" results in the plasticity.

Thanks to @By137 for correcting my misunderstandings regarding "plastic" and
"method".

