smt贴片问题

[mcblog]

硬件PCB开源方面有些疑问：理解贵团队硬件开源BOM文件时可能是按照当时的环境生成的半成品+后期自己加工，在我们进行PCB、SMT贴片工艺时以及跟PCB厂商多次沟通发现一些问题寻求帮助。 1、根据提供的BOM,发现在JLC smt贴片时有几样需要确认

不贴是否影响使用？ 2、异常器件默认不贴是否影响使用？

3、是否会更新硬件部分内容，以达到任何人都可以直接通过提交相关文件给厂商 实现在默认配置下打板即可（不考虑元器件无货的情况）。或者是否有现成产品以便直接购买使用及测试？

[wanming2008]

1:MC3662，tja1081不贴肯定影响使用，这2个是接口芯片。不贴会影响总线功能。每个贴片厂的贴贴片不同，需要您自己和贴片厂沟通适配。这个芯片一般贴片厂都买不到。需要您淘宝或者digikey购买后寄给贴片厂 spc5748是主芯片，不贴肯定影响使用，你这个错误和bom无关，是贴片厂没有元器件导致的。同样需要自行购买后寄给贴片厂，其他带有nc字样或者一些jp插头都是测试点的都可以不贴片。并不会影响功能的使用。核心是那2个DB9的接头需要连接。 2：D30和D31如果您使用usb C口供电是不需要贴片的。 如果使用OBD供电的话，看使用哪一个obd，如果是J17这个OBD的12V供电就需要贴片D30 如果是使用J31这个obd供电就需要贴片D31，我们是默认贴片的因为我们的应用和您的不一定相同。 如果用usb供电这2个都不贴。这里是非常重要的，因为如果贴错可能上电就烧毁了 3：我们会本周更新一个bom的精简版本，删除可以不贴的元器件，以防止误贴片。这样根据精简版本的bom贴片就一定不会贴错。就算少贴了也不会造成贴出来的芯片短路或者烧毁的情况。至于您提到的文件直接交给厂商就可以打板子的问题，首先PCB肯定是可以直接打板的。贴片的话，每个人的贴片厂不同，包括我们自己也没有做到一次贴片成功。除非批量化300片，1000片这种小批量贴片工厂才会配合我们。所以我们还是建议贴片时候和贴片厂一起核对问题，然后针对具体的问题，来讨论细节。 比如D30和D31的贴片。您提出了这个问题，我们就可以及时沟通， 但我bom中无论写贴还是不贴都可能给obd供电的测试人员带来误导，产生烧毁pcb板子的情况。特别是主芯片mpc5748价格昂贵。 4：目前我们没有量产autosuite的计划。 但是您贴片时候有任何的具体的具体问题都可以在这里提问。比如D30这种。 autosuite确实只是一个简单的工具。还未到直接量产的能力，软件也有很多功能没有开发完成。后续更新需要我们投入更多的人力和物力，但是目前我们没有太多的时间全职支持autosuite的开发功能。所以目前状态下确实需要使用者有一些技术功底。 最后感谢您的建议。

1: MC3662 and tja1081 will definitely affect their use if not pasted. These two are interface chips. Not pasting will affect the bus function. Each patch factory has different patches, and you need to communicate and adapt with the patch factory yourself. This chip is generally not available to SMT factories. We need you to purchase from Taobao or Digikey and send it to the SMT factory

SPc5748 is the main chip, and not sticking it will definitely affect its use. Your error is not related to BOM, but is caused by the lack of components in the chip factory. You also need to purchase it yourself and send it to the SMT factory. Other products with the words "nc" or some JP plugs that are test points can be SMT free. It will not affect the use of the function. The core is that the two DB9 connectors need to be connected.

2: D30 and D31 do not require a patch if you use a USB C port for power supply.

If using OBD power supply, it depends on which OBD is used. If it is the 12V power supply of the J17 OBD, a D30 patch is required

If using J31 for OBD power supply, we need to mount D31. We default to mounting because our application may not be the same as yours.

If using USB power supply, neither of these two will be connected. This is very important because if it is pasted incorrectly, it may burn out when powered on

3: We will update a streamlined version of BOM this week, removing components that can be left unused to prevent incorrect placement. This way, based on the simplified version of the BOM patch, it will definitely not be pasted incorrectly. Even if it is not pasted, it will not cause a short circuit or burning of the pasted chip. As for the issue of directly submitting the documents you mentioned to the manufacturer to be printed, PCB can definitely be printed directly. When it comes to patches, everyone's patch factory is different, and we ourselves have not achieved a single successful patch. Unless we mass produce 300 pieces or 1000 pieces, small batch SMT factories will cooperate with us. So we still suggest checking the issue with the SMT factory during the placement process, and then discussing the details based on the specific issue.

For example, the patches for D30 and D31. If you raise this issue, we can communicate in a timely manner,

But whether I write or do not paste in my BOM, it may mislead the testing personnel of OBD power supply, resulting in the situation of burning the PCB board. Especially the main chip MPC5748 is expensive.

4: At present, we have no plans to mass produce autosuite.

But if you have any specific questions when pasting, you can ask them here. For example, D30.

Thank you for your suggestion.