Greg, I know you’re a good guy and you mean well so please consider this good spirited feedback. We all appreciate the direct experiences and details you’ve shared about your Longmill journey. However I did want to address your recent comment in this thread:
I hope you have never had a fire or required the services of first responders. Even if you haven’t, I suspect you still appreciate the existence of the fire department.
Likewise I hope you’ve never needed a crumple zone or an airbag, but I think we can all agree that they improve the overall risk/benefit of driving a vehicle. Things don’t have to be directly applicable to one individual unique situation to be relevant to a broader community like the one Sienci is building around the Longmill. It takes a village to raise a product.
A general Internet forum rule of thumb is: If a topic isn’t applicable to you or you can’t add value, it’s more helpful to stay silent. If someone is way off base, they will get silence from everyone and the topic will fade away in to the archives. Conversely, everyone is typically welcome to join the discussion when they have value to add or for the occasional witty retort or social banter that adds a bit of personality to a community.
It isn’t particularly helpful to say “I don’t need that, so why bother?”. The silence covers that. Also, saying that can be construed as diminishing the contributions of others, some of which will prove to be highly relevant to many people in the community, even if this particular item doesn’t fit your needs.
At best, a phrasing of “That’s interesting, I’m not sure I’d have a use for it, but help me understand why you would want that. Maybe there is another way to solve the problem?” would be better received and indicates (what I believe to be) your desire to be helpful.
Nonethless, to help illustrate the relevance of the topic, I’ll share a few examples with you that will almost definitely apply to some of the current and likely future Longmill buyers. We all benefit when the community (and Sienci Labs) continues to grow. I’m all for a big tent, but even without it, here are some examples:
- Acoustic limitations / Noise By-laws
Home (and some small business) CNC users may have (as I do) municipal noise bylaws that are fairly limiting and aggressively enforced. Folks in my situation can only be cutting during certain hours of the day and certain days of the week. They may even be limited in how long they can create a certain level of noise. So having an accurate time estimate is critical to planning when you can cut which toolpaths, which may require multiple stops and starts over multiple days to finish a whole job. This allows you to organize the tool paths to fit the restrictions.
- Space Limitations
Not everyone has the luxury of a full time shop. Many of us (me included) have taken over all or part of the family garage to create a work space. At times that space is required for other family (and automotive) purposes. The beauty of the Longmill being a manageable size and somewhat mobile allows for creative mounting and even (vertical) operation options. However, operation in any orientation will likely cause noise, space and dust/safety conditions that block other family activities in the garage. If you can’t accurately predict the cut times and play nicely with others users of the space then the SAF (spouse acceptance factor) trends towards zero and friction occurs.
- Job Scheduling
For anyone doing work that they hope to be paid for, it’s always the trinity of time, cost and quality (pick any two).
Once you build a backlog of business, it is critical to know approximately how long the machine will be engaged on a given job so you can accurately estimate how soon you can do the subsequent job. If I have jobs A, B and C committed and roughly scheduled and then someone requires a rush for job D (or to move up A, B or C) - I can determine if I can accept the job by considering the impact on the other clients and the committed timelines. Without this, I am blind. For something a little closer to home, @chrismakesstuff would never have been able to consistently deliver the tally of machines shipped (and keep the hungry hoardes at bay) if he didn’t have an excellent handle on inventory levels, sub-system build and assembly times and final packaging times.
This is a fairly common business issue in many fields, but given that the CNC is a big computer, which is a big calculator that uses known quantities to perform it’s duties, we should be able to feed it the right inputs to allow it to accurately estimate. We just need to collect enough data to get us in to the right general zone… which brings us back to the original purpose of this thread, to start that discussion.
- Cost / Opportunity Cost
Whether home users, semi-commercial or commercial users we all run in to cost & opportunity cost analysis. Any job is only worth a given amount of time and effort and beyond that you may discard it or choose to address the requirement in a different fashion (or not at all). As I often say “I’d like to do X but it’s not a $500 problem”.
You can’t make an informed decision about options if you don’t have a rough order of magnitude of the time/cost invovled (and by extension the opportunity cost of what else the machine could be doing or what else you could be doing with the time and money the job would consume). As an example, I suspect a number of users here have access to other (often larger/faster) CNC options at work or at a maker space, but those have different capabilities, costs and time/access quantum associated with them. I need to know what the Longmill option will consume in time so I can compare. It won’t be everything to everyone on every job.
- CAM Operation Selection & Trade-offs
There are often multiple roads that lead to Rome. Many desired outcomes could be achieved in more than one way, for example a drill or bore or even pocket operations for bench dog holes. Depending on the level of detail and finish passes and acceptable cost for the given job, one is preferable to the others. When doing the CAM programming it is helpful to be able to compare two adjacent roads that both contain some trade-offs against their respective operation times (and everything tied to those operations times, as noted above). Fusion 360 is great for integrating all this in one spot in the simulator so you can compare and contrast options while “proof reading” the programming.
I’m sure others could chime in with examples of why they would appreciate or even require relatively accurate time estimates. While I appreciate that you have the apparent luxury of relatively unlimited time, space and finances that make machine time estimation of little interest - most of us are not yet so fortunate and would appreciate accurate times.
Finally, the overall market appeal of the Longmill and it’s potential to appeal to as broad a potential customer base as possible suggests this is important. Many objections stopping people from buying can be addressed directly or indirectly when an operator can accurately predict machine time. So, there is that…