But I'm desperately trying to figure out what the tangible benefits to owning one is. Because clearly there are people who believe there is. But as yet, nobodys provided a 'full cycle' story about how it helps.
What is this machine useful for. how could i justify it to my boss.
What is this machine useful for. how could i justify it to my boss.
If you can't think of any reasons then I don't think it's for you. I've contemplated this kind of machine even in the day and age of quick turn protos, oshpark, etc.
What is this machine useful for. how could i justify it to my boss.
If you can't think of any reasons then I don't think it's for you. I've contemplated this kind of machine even in the day and age of quick turn protos, oshpark, etc.
I can think of multiple reasons why there is appeal to this machine. The lure of nearly instant results. the concept that you can have something much faster than you think you coudl previously. There was a time i thought this would be amazing.. Running lots of prototypes is expensive. ( lets exclude materials they actualy are not much more than a rounding error for lots of stuff compared to the cost of time ). When its easy to run prototypes ( like using a mill ) the tendency is that the quality of engineering goes down. The we'll work it out and see what happens approach...
Im convinced that spending more time on actual engineering and produce higher quality work acutally saves time and money overall. Rush jobs never quite hit the quality level, because they are just that.. rush jobs.
It's time to finish this thread, already advertised the obsolete machine, very few interests let's go forward,
What is this machine useful for. how could i justify it to my boss.here again... https://www.eevblog.com/forum/reviews/prometheus-for-rapid-prototyping-forget-everything-you-know-about-pcb-milling/msg1189948/#msg1189948 and nobody is forcing you to justify it to your boss...
i just realized the OP claim 5 mils tolerance, i believe this is highly optimistic value. we need proof for that. in the video already showing inconsistencies in isolation/mill thickness, that i estimate between 0.5mm - 1mm milling. 20 mils (0.5mm) tolerance maybe believable/achievable. my 0.5mm drill bit may break at an instant.
IMHO there is no reason to over-obsess about minimal widths. A board needs to be soldered as well and very small clearances are easy to bridge. When I etch a prototype I use minimal clearances of 0.25mm and preferably much more.
IMHO there is no reason to over-obsess about minimal widths. A board needs to be soldered as well and very small clearances are easy to bridge. When I etch a prototype I use minimal clearances of 0.25mm and preferably much more.
IMHO there is no reason to over-obsess about minimal widths. A board needs to be soldered as well and very small clearances are easy to bridge. When I etch a prototype I use minimal clearances of 0.25mm and preferably much more.It's about margin - if a system will only just do 10mil/0.25mm, chances are it will be unreliable long-term if you expect it to do dense boards with those design rules.
However if it will comfortably do half that, chances are you will get a good yield from more relaxed design rules, and the capability to go more dense when necessary.
IMHO there is no reason to over-obsess about minimal widths. A board needs to be soldered as well and very small clearances are easy to bridge. When I etch a prototype I use minimal clearances of 0.25mm and preferably much more.I agree with that in general - it's always good to design with larger trace/space if you can do it. Though minimal trace and space can become very important if you select components that have smaller clearances between their pads (or if they only come in smaller packages). For example, many QFPs have a clearance between pads in their recommended footprints of only .2 mm (8 mils) or less, so in those cases if your machine only supports 10-mil spaces you won't be able to do it at all.
It's about margin - if a system will only just do 10mil/0.25mm, chances are it will be unreliable long-term if you expect it to do dense boards with those design rules. However if it will comfortably do half that, chances are you will get a good yield from more relaxed design rules, and the capability to go more dense when necessary.
IMHO there is no reason to over-obsess about minimal widths. A board needs to be soldered as well and very small clearances are easy to bridge. When I etch a prototype I use minimal clearances of 0.25mm and preferably much more.I agree with that in general - it's always good to design with larger trace/space if you can do it. Though minimal trace and space can become very important if you select components that have smaller clearances between their pads (or if they only come in smaller packages). For example, many QFPs have a clearance between pads in their recommended footprints of only .2 mm (8 mils) or less, so in those cases if your machine only supports 10-mil spaces you won't be able to do it at all.In case of prototypes you'll always have to be creative. A QFP has a 0.5mm pitch so if you have a space of 0.25 between the pads there is still 0.25mm of pad width. Not a real problem and the bigger spacing will probably improve the solderability of the board as well (*). Don't mix absolute accuracy and minimum clearance here.
(*) Not every contract assembler is happy with the manufacturer's PCB footprints!
QuoteIt's about margin - if a system will only just do 10mil/0.25mm, chances are it will be unreliable long-term if you expect it to do dense boards with those design rules. However if it will comfortably do half that, chances are you will get a good yield from more relaxed design rules, and the capability to go more dense when necessary.Yes, I'd agree with that. I think most/all of the high end machines from T-Tech and LPKF advertise 4 mil trace capability, even on old machines like my 7000S from the mid 1990s. But I think it is worth mentioning that things get very expensive very quickly if an attempt is made to mill using a 4 or 5 mil end mill to get a tiny trace and width across loads of address and data lines on a large and complex CPU design for example. You might end up using three tools to finish the PCB.
The price of the 4 mil end mills (eg $320 for 10) is nearly three times that of a 31mil end mill and about double the cost of a 15 mil end mill from T-Tech and these tiny 4 mil end mills have a much reduced life. Things get much worse on materials like Rogers 4003C or 4350 if you use fine end mills because the wear rate is much higher still. I think the top grade LPKF tools are even more expensive but at my place of work this isn't an issue. We just buy what we need. The bonus for me is that I can salvage the part worn tools from work for free so I rarely buy new tools here at home. I think the LPKF tool timer is very aggressive so I often get tools with loads of life left in them and I get them at a rate that far exceeds my usage at home. The only tools I won't salvage are drills and contour routers. I always buy these new and they are generally quite cheap anyway.
Thats quite impressive Rocco, given the price of the machine. nice work.
The other thing is that it's worth trying to find the optimal spindle motor spin speed and tool travel speed for each type of board material and tool type.
T-Tech gave me this data many years ago although I was scared away by the very high tool travel speeds they were suggesting. A case of my ignorance of what is OK against what seems 'not OK' when you watch the machine going that fast. So I tend to run my machine slower. Also it's worth having a fast/variable motor speed. One limitation of my old machine is that it is stuck at 23k rpm max.
Also, if you want to produce some nice marketing samples then try doing some pretty looking RF filters on Rogers 4003C as it looks very professional once milled. The white substrate against the clean copper looks great especially if the cuts are clean. I often feel a bit sad when soldering parts to the board because it spoils the beauty of a freshly milled board on 4003C
Who's mixing accuracy and minimum clearance? You're saying that the recommended clearance isn't really the minimum. That's fine, it's good to get creative if you have to. I truly applaud it. There are reasons to do use a larger bit and not to obey recommended footprints, like faster milling speed and cheaper bits. But I know you're not asking me to apologize for making a more capable tool that has the ability to do fine trace and space if you need it. It's not like I'm charging more money for it! Right?? It's only an option, there if you need it.
Who's mixing accuracy and minimum clearance? You're saying that the recommended clearance isn't really the minimum. That's fine, it's good to get creative if you have to. I truly applaud it. There are reasons to do use a larger bit and not to obey recommended footprints, like faster milling speed and cheaper bits. But I know you're not asking me to apologize for making a more capable tool that has the ability to do fine trace and space if you need it. It's not like I'm charging more money for it! Right?? It's only an option, there if you need it.No need to get upset. A big part of running is business is managing the customer's expectations. Ofcourse you are proud of what you have made (as an engineer with appreciation for mechanical stuff I think you should be) but IMHO you are way too focussed on the narrow clearances which will lead to dissapointed customers because of the high wear on milling bits and slow speed. Customers really don't care that you devoted a lot of time and effort in getting it the way it is especially if the machine is slow and eating tools. This is probably one of the things LPKF has done wrong so don't repeat that mistake.
A better approach would be to paint a more balanced picture where potential customers can get a good feel on the tradeoffs between speed, tool wear and minimum clearances.
Customers really don't care that you devoted a lot of time and effort in getting it the way it is especially if the machine is slow and eating tools. This is probably one of the things LPKF has done wrong so don't repeat that mistake. A better approach would be to paint a more balanced picture where potential customers can get a good feel on the tradeoffs between speed, tool wear and minimum clearances.
Thats quite impressive Rocco, given the price of the machine. nice work.
I'm happy to share pictures of the 5-mil isolation! Here are two (which you can also view on www.zippyrobotics.com):