I have several questions that I would like to discuss. The first is how long it should take to assemble a cabinet. I ask this because I have read several posts where a single man is putting together 20-40 cabinets a day. On a good day we can sometimes get 16-18 complete with two guys. We have a four man frameless company (three shop and one in the office) and here's how we do it.
Step 1. Cut, sand, and finish all finished parts: Applied ends (CNC), toe kicks, fillers, doors(outsourced sometimes they are here on time, most times they are late because of short lead times), and any other parts that might need finished. Itís done usually with two guys, sometimes three depending on the size of the project.
Step 2. Cut all drawer box parts. We cut long strips with grooves (CNC) and cross cut them on the table saw. All strips are edge banded through a scmi 212 bander. Drawer bottoms are sometimes cut by hand if there is enough scrap laying around, otherwise they are CNC cut and done by one guy.
Step 3. Assemble all the drawers we pocket screw the sub-front and backs all in one session. Assembly is four or six pocket screws with a few pins to initially align the parts. Then we staple along the groove to hold the box square. It takes 13-14 minutes a sheet for the strips to be cut (the CNC can only cut at 600ipm) and an additional 15 minutes per drawer to the edgebanding and other operations. This does not include drawer hardware install which takes an additional 3-4 minutes per drawer. This is done with one guy.
Step 4. Started as soon as the drawer strips have left the cnc. We cut all cabinet sides, tops, bottoms, shelving, and backs. Cabinets sides have all shelving and drawer slide holes. We used to cut all parts via cnc but it always takes to long to sort all the drawer parts, nailers, and strechers off the cnc table. We average about 18 minutes per sheet with one guy.
Step 5. Edge band all cabinet parts from step 4. Iíve never actually timed this but probably less than an hour with two guys.
Step 6. Hinge bore all doors.
Step 7. Assemble cabinetry. All cabinet parts are pulled from vertical stacks that are close to the assembly table. We attach all hardware while the sides are flat. All cabinets are then pinned to align parts. Then pre-drilled and screwed. Backs are plant on with nailer strips pinned and screwed. All drawers are put in and fronts aligned, then pinned on through the sub front and screwed on. We pull them back out and use a jig to drill for all pull/knob locations. Then put the drawer back in. If the cabinet has doors they are attached and drilled for pull/knobs. All fronts are adjusted. Applied and fillers are attached. Then we shrink wrap the cabinet a stack them ready to be delivered. This is if the door and drawer fronts are here on time, otherwise we do everything above except attach them. This causes us to handle the box twice. Average time is between 45 minutes to 1 hour per box for assembly time.
Step 8. Install.
In the office we recently switched to Cabinet Vision Solid 4.2, and the learning curve has been fairly steep. Mistakes have been made in the leaning process that has caused the guys to be very watchful of the cutlists and parts which I know slows us down even more. Mistakes are getting fewer with each job. Please fill free to be a critic and offer any insight that you can offer. I know that we can do better. I have read some about work in progress and it all sounds good in theory but does seem real applicable to a shop our size.
How would you all attack a kitchen - all at once or batch? If you batch could you explain how that is beneficial vs. all the extra set ups?
List of Equipment:
(Business and Management Forum)
From contributor G:
I'm pretty sure when they say they can assemble 20-40 cabinets in a day they mean all the parts have been milled. All they are doing is assembling.
Cabinet vision has a nice ucs that makes the Zargen system a snap. It will end your drawer bottle neck. It will also drill the holes to mount drawer guides (with euro screws) in your gables, on the CNC. You have a Grass Euro Press I assume? If that be the case then you just need a couple 10 mm bits to bore the drawer fronts and a Grass ram for pressing the drawers together. Imagine five minutes per drawer, done! If you were to go this route you could save enough time to utilize your door equipment and bring doors back in house and they won't be late anymore.
Use Cabinet vision to pre drill as many holes as you can on the CNC. You mention you have a drill on the CNC, if it is just one single drill make it a 5mm. 5mm drill works for guide, hinge plates and pre drill holes for screws.
All in all, I think you guys are flying, and I mean cruising, but if your goal is to get faster- I think the Grass drawer system is a huge gain, and I would get the Cabinet Vision thing straightened out before it hits the floor, you are wasting valuable production time having someone analyze cutlists- run a small test job in CabVis and keep working out the bugs, then re-introduce it bug free. This would do many things for you and of course a completely cut job is a major bonus in assembly.
We cut all parts requiring milling (dowel holes, dadoes, shelf holes, hinge holes etc.) on a nested CNC. We cut all non milled parts on a beam saw (decks, cleats toe kicks, adjustable shelves etc.). Edgeband , dowel, finish room assembly, hang doors and drawers (grass systems mostly), wrap, organize on a pallet and ship.
Your performance with two guys equals 16 boxes divided by 16 hours which equals one box per labor hour - very good rate. Contributor F your performance is also good at 16 boxes divided by 24 hours equals .66 boxes per labor hour. Everyoneís process is slightly different, but by using an internal method for measurements of performance you can easily gage the impact that procedural changes has made on your performance.
From the last job that we did the time broke out something like this. (I'm at home so I'm going off memory). 8.5 hours to construct 28 drawer boxes (this includes rollouts) and attaching ball bearing slides. This doesn't include the actual CNC cutting of the drawer box strips, which was an additional 65 minutes. So the total time involved was 575 minutes or 20.5 minutes per box.
3.5 hours to construct a knee wall. Attach the applied backs and attach the corbels. This job had thirty two cabinets. It had five, four drawer bases, one drawer over cake tray cabinet, one drawer over trash can cabinet, three sink base cabinets one with tipout trays, two base Lazy Susan cabinets with turn tables, two base cabinets drawer over rollouts, three cabinets stacked to make a pantry the base had three rollouts the middle was open and the top would be a extra depth upper cabinet, eight upper cabinets with shelves one was a refer cabinet with finished sides, two upper Lazy Susan cabinets with shelves, one base cabinet with a shelf, two linens with shelves, and two base cabinets that made up a bench seat. This was a new construction house with a kitchen, two bathrooms, utility room, and a window bench seat. The cutting time for this project was 444 minutes with the 3/4" melamine taking 18 minutes a sheet to cut, vacuum of the table, and put a new sheet on, the 1/4" melamine taking 12 minutes per sheet with the same steps as the 3/4". There were 20 - 3/4" and 7 - 1/4" sheets.
These 32 cabinets were assembled by two people. Assembly includes putting hardware on the sides, aligning the cabinet parts with pins, then pre-drilling all the holes for screws by hand, screwing the cabinet parts together, planting on the backs with pins that are aligned then pre-drilled and screwed, pin on the nailer strips pre-drilled then screwed, put in all drawers and accessories, hang all drawer fronts, doors, applied ends, fillers, and all hardware. Itís basically a completely finished cabinet. Total time for all of this was 53 hours (not a typo, I don't think that I clearly stated the problem above). This is nearly 1.75 hours per cabinet just for assembly. Laminate counter tops took an additional 20.5 hours to complete. The installation took another 60 plus hours. Total job time was approximately 153 hours. This job was thermofoil so there was zero finishing.
Thanks to some of the advice we have gotten here, which we are truly thankful for we have developed some new systems that have dramatically changed some of these numbers. Here is what we tested and changed.
We had our sheet good supplier sample us out two sheets of 3/4" UV birch and one sheet of 1/2" UV birch. Both sheets are finished two sides, so that they are balanced and less likely to warp. The 3/4" is for sides, tops, bottoms, stretchers, and nailers, and the 1/2" is for drawer bottoms and backs. We have to use 1/2" because we only have a single tool machine and this eliminates the need for a bit change. We decided to test a 381mm(15") four drawer base because there are several small parts and with a melamine sheet these we a nightmare to hold. This is why we switched to cutting the drawer parts into strips rather than individual parts. The test sheet had a total of 23 parts to cut. The sheet did have a slight cup of about 1/4" over the length of the sheet. We decided to make it difficult for the vac table and faced the cup up. To our surprise the sheet pulled flat with the vacuum on (12hp). We always had to face the cup down with 3/4 melamine. I think that has to do with melamine being a more rigid product. We started cutting with a trigger finger on the hard stop button just in case parts started flying. To our surprise not a single part moved and on top of that the spoil board was in bad condition and needs to be resurfaced. The smallest parts cut were a drawer sub-front and drawer back 110mm x 286mm (.39 sq feet of surface area). I must mention that all the parts were cut in two passes, leaving a .5mm onion skin and the part .2mm over sized. The second pass finished everything precisely. The modifications made were: we cut drawer parts individually rather than strips, nailer and stretchers were also cut, we grooved all the drawer parts, we add grooves to the cabinet sides and the bottom, and we added assembly boring through holes for screw placement.
The results were dramatic - 23 minutes to cut the sheet (five minutes per sheet slower). We averaged the cutting time to all 23 three parts and just called it one minute per part.
The results for the drawer box:
20 minutes to cut all 20 parts (includes the bottoms)
Five minutes to edge band 16 drawer parts
Two minutes to pocket hole eight drawer parts
Twelve minutes to assemble four drawers
Eight minutes to attach slides.
This included all transportation of parts as well.
Total time 47 minutes and that equals 11.75 minutes per drawer a savings of 8.75 minutes. I must also note that we purposely tried to go slow to better simulate an employee. Also you might have noticed that my first post said something like 15 minutes per drawer. In that example he was being time over 41 drawers, and in this example it was 28 drawers untimed. I actually think the timer alone saves me five minutes a drawer.
Next was the attachment of the drawer slides to the case and the total time was eight minutes. Assembly of the case was six minutes. The addition of the through-holes and the grooving for the back saved a tremendous amount of time, and the screws counter sink like butter. We have a delta 14 spindle line borer that we are going to test and see if it can be used as a horizontal borer. The CNC operator could bore the parts for alignment dowels after they came off the CNC while he is waiting on the next sheet to finish cutting. Don't know if this will be an accurate enough setup but we will try and report the results.
Total time from raw materials to assembled cabinet was 61 minutes. At this phase we have a cabinet carcass with four drawers in it. It was taking 1.75 just to assemble the cabinet. If I add into this the drawer construction and the sheet cutting this goes up to 3.46 hours per cabinet. This all leads me to question where the other 2.46 hours are. I know that these changes have significantly speed things up. We still have to be losing a tone of time in the attachment of the fronts, applieds, and pulls. We plan to do more investigation on the attachment of the fronts, applieds and pulls, and will report the results so hopefully all can benefit.
A couple of side notes:
The UV birch sheets were within .2mm thickness and checked in several locations because of concerns over the uniformity of sheet. My partner also made a new cart that would allow us to rack parts vertically rather than horizontally. Some of the melamine parts moved. They measured 12" x 12" 1sq ft 60% more surface area than the smaller UV drawer parts. This made us question whether the UV birch parts might have more friction when sliding that the melamine parts when we pushed the parts across the spoil board gently by hand. The UV part clearly had less friction than the melamine part of the exact same size. When we applied vacuum to the parts the UV birch was difficult but still easier to budge than the melamine part. However if you tried to pick the part straight up, you could get the melamine part to lift, but you couldn't budge the UV birch part. Any thoughts on this? Could this be why the larger melamine parts moved when cut by the CNC, but the much smaller UV drawer parts didn't? Do you actually have more hold down strength with a material that is more permeable? I was always under the impression that the less air moving through or around parts was better.