How to improve machine design estimates, workflow
One of the most difficult tasks in project management and quoting machinery is determining how long the project will take to complete and what resources will be required. Estimates directly impact the bottom line as well as determining whether you get the job at all.
If you underestimate the time it will take to complete the job you will probably lose money on the project. The customer will also not be happy when you are late. If you pad the schedule it reduces the chances of getting the job in the first place.
As you can see from figure 1, adding resources may help shorten the schedule and keep the customer happy, hopefully without impacting the resource cost too much. You may have also heard the saying "Nine women can’t make a baby in a month." As you can see from the above chart, this is clearly not true.
Figure 2 is a better example of a typical machinery project. As you can see, while there are tasks and phases that can run concurrently, many tasks also depend on completion of a previous task. Many of the milestones are non-negotiable: you can’t start building something until you have parts to build it with. You can’t start wiring a machine until there is a machine to wire. You can’t start debug until the machine has been powered on and is substantially completed.
There are other tasks that are somewhat flexible. Sometimes more resources can be added to shorten the time it takes to complete a task. Maybe the vendor materials can be expedited or substituted. People can work longer shifts. It is important that the person making these estimations and adjustments understand the limitations of their resources however. Just because your assembly guy happens to know a little bit about PLC programming and has some free time doesn’t mean you can shorten the time it takes for software development. Then again, maybe it does… it depends on the type of project and the ability of the resources.
Probably the most critical part of making time estimations is a history of how long it has taken to complete similar tasks in the past. Once you have done lots of projects and kept good records you will have a good idea of how long different tasks will take given your existing resources. Often it is then a matter of scaling hours estimates based on different parameters such as I/O and actuator counts, weight or lengths of steel or extrusion, numbers of fasteners, etc. This will often get you in the ballpark as far as a total number of hours by discipline.
Then there is the matter of making sure your personnel have available the number of hours required for the job. Obvious problems like double booking someone can be handled in the scheduling software (I use Microsoft Project). What is not so obvious is the time it takes for people to mentally switch from one project to another. It is fine to say that a controls or software engineer can work on three different projects at once, but in my experience this is often less than efficient. On the other hand, if a design engineer is assigned to a project for its full duration, they will usually find a way to fill all of the assigned hours whether working on the project or not. This is also not very efficient.
The bottom line on estimations of time and resources on projects is that it takes a lot of experience to accurately project how long a project will take to complete. This starts with the applications department: they strike the first balance between ensuring that the project can be completed on time using existing or contract resources and not throwing so many hours at a job that the price or schedule is unacceptable to the customer. Most complex quotes are reviewed by a committee of technical and management people to help strike this balance.
The next part of the equation is management of the project to ensure that time lines are held to and resources are used efficiently. While this is often accomplished by Project Managers, resources may be used across multiple projects with different managers. This often requires coordination between different departments.
There are a variety of tools that can be used to help in the quoting and project management disciplines. Microsoft Project is an excellent method of allocating hours and resources, while Excel can be used to create applications spreadsheets and resource forecasts. Part of a software project that I have been working on also addresses resource usage and allocation.
– Edited by Anisa Samarxhiu, digital project manager, CFE Media, firstname.lastname@example.org